本文内容
- 环境
- 项目结构
- 演示下载
- 参考资料
本文是 github 上 和 项目的一部分，将下载部分分离出来，看看如何实现。（不知道此人学了多久，Android 水平不低~ 貌似年龄跟我差不多~
）
假设，现在有个下载 apk 包的需求，你大概能想到什么？
- 下载本身；
- 下载进度；
- 期间还能取消；
- 由于网络不好或中断，下载失败，还要能重试；
- 因为下载的是 apk，下载完还要能提示安装更好，而且，很多手机管理 app，还能静默安装；
- 还能在手机通知栏看到下载提示；
- 这些就涉及到 、 和 。
自己 调试一下~
环境
- Windows 2008 R2 64 位
- Eclipse ADT V22.6.2，Android 4.4.2（API 19）
- SAMSUNG GT-8618，Android OS 4.1.2
项目结构
图 1 项目结构
图 2 主程序
图 3 下载
（注意：顶部通知栏，是有下载图标的~）
package com.example.download.ui;
import java.io.File;
import java.text.DecimalFormat;
import com.example.download.R;
import com.example.download.utils.DownloadManagerPro;
import com.example.download.utils.PreferencesUtils;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.DownloadManager;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
/**
* DownloadManagerDemo
*
*/
public class DownloadManagerDemo extends Activity { public static final String DOWNLOAD_FOLDER_NAME = "Trinea";
public static final String DOWNLOAD_FILE_NAME = "MeiLiShuo.apk";
public static final String APK_URL = "http://img.meilishuo.net/css/images/AndroidShare/Meilishuo_3.6.1_10006.apk";
public static final String KEY_NAME_DOWNLOAD_ID = "downloadId";
private Button downloadButton;
private ProgressBar downloadProgress;
private TextView downloadTip;
private TextView downloadSize;
private TextView downloadPrecent;
private Button downloadCancel;
private DownloadManager downloadManager;
private DownloadManagerPro downloadManagerPro;
private long downloadId = 0;
private MyHandler handler;
private DownloadChangeObserver downloadObserver;
private CompleteReceiver completeReceiver;
@Override
protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);
setContentView(R.layout.download_manager_demo);
handler = new MyHandler();
downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
downloadManagerPro = new DownloadManagerPro(downloadManager);
// see android mainfest.xml,
// accept minetype of cn.trinea.download.file
Intent intent = getIntent();
if (intent != null) { /**
* below android 4.2, intent.getDataString() is
* file:///storage/sdcard1/Trinea/MeLiShuo.apk
* equal or above 4.2 intent.getDataString() is
* content://media/external/file/29669
*/
Uri data = intent.getData();
if (data != null) { Toast.makeText(getApplicationContext(), data.toString(), Toast.LENGTH_LONG)
.show();
}
}
initView();
initData();
downloadObserver = new DownloadChangeObserver();
completeReceiver = new CompleteReceiver();
/** register download success broadcast **/
registerReceiver(completeReceiver, new IntentFilter(
DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}
@Override
protected void onResume() { super.onResume();
/** observer download change **/
getContentResolver().registerContentObserver(
DownloadManagerPro.CONTENT_URI, true, downloadObserver);
updateView();
}
@Override
protected void onPause() { super.onPause();
getContentResolver().unregisterContentObserver(downloadObserver);
}
@Override
protected void onDestroy() { super.onDestroy();
unregisterReceiver(completeReceiver);
}
private void initView() { downloadButton = (Button) findViewById(R.id.download_button);
downloadCancel = (Button) findViewById(R.id.download_cancel);
downloadProgress = (ProgressBar) findViewById(R.id.download_progress);
downloadTip = (TextView) findViewById(R.id.download_tip);
downloadTip
.setText(getString(R.string.tip_download_file)
+ Environment
.getExternalStoragePublicDirectory(DOWNLOAD_FOLDER_NAME));
downloadSize = (TextView) findViewById(R.id.download_size);
downloadPrecent = (TextView) findViewById(R.id.download_precent);
}
private void initData() { /**
* get download id from preferences.
* if download id bigger than 0, means it has been downloaded, then
* query status and show right text;
*/
downloadId = PreferencesUtils.getLong(getApplicationContext(), KEY_NAME_DOWNLOAD_ID);
updateView();
downloadButton.setOnClickListener(new OnClickListener() { @Override
public void onClick(View v) { File folder = new File(DOWNLOAD_FOLDER_NAME);
if (!folder.exists() || !folder.isDirectory()) { folder.mkdirs();
}
DownloadManager.Request request = new DownloadManager.Request(
Uri.parse(APK_URL));
request.setDestinationInExternalPublicDir(DOWNLOAD_FOLDER_NAME,
DOWNLOAD_FILE_NAME);
request.setTitle(getString(R.string.download_notification_title));
request.setDescription("meilishuo desc"); request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setVisibleInDownloadsUi(false);
// request.allowScanningByMediaScanner();
// request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);
// request.setShowRunningNotification(false);
// request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_HIDDEN);
request.setMimeType("application/cn.trinea.download.file"); downloadId = downloadManager.enqueue(request);
/** save download id to preferences **/
PreferencesUtils.putLong(getApplicationContext(), KEY_NAME_DOWNLOAD_ID,
downloadId);
updateView();
}
});
downloadCancel.setOnClickListener(new OnClickListener() { @Override
public void onClick(View v) { downloadManager.remove(downloadId);
updateView();
}
});
}
/**
* install app
*
* @param context
* @param filePath
* @return whether apk exist
*/
public static boolean install(Context context, String filePath) { Intent i = new Intent(Intent.ACTION_VIEW);
File file = new File(filePath);
if (file != null && file.length() > 0 && file.exists() && file.isFile()) { i.setDataAndType(Uri.parse("file://" + filePath), "application/vnd.android.package-archive");
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
return true;
}
return false;
}
class DownloadChangeObserver extends ContentObserver { public DownloadChangeObserver() { super(handler);
}
@Override
public void onChange(boolean selfChange) { updateView();
}
}
class CompleteReceiver extends BroadcastReceiver { @Override
public void onReceive(Context context, Intent intent) { /**
* get the id of download which have download success, if the id is
* my id and it's status is successful, then install it
**/
long completeDownloadId = intent.getLongExtra(
DownloadManager.EXTRA_DOWNLOAD_ID, -1);
if (completeDownloadId == downloadId) { initData();
updateView();
// if download successful, install apk
if (downloadManagerPro.getStatusById(downloadId) == DownloadManager.STATUS_SUCCESSFUL) { String apkFilePath = new StringBuilder(Environment
.getExternalStorageDirectory().getAbsolutePath())
.append(File.separator)
.append(DOWNLOAD_FOLDER_NAME)
.append(File.separator).append(DOWNLOAD_FILE_NAME)
.toString();
install(context, apkFilePath);
}
}
}
};
public void updateView() { int[] bytesAndStatus = downloadManagerPro.getBytesAndStatus(downloadId);
handler.sendMessage(handler.obtainMessage(0, bytesAndStatus[0],
bytesAndStatus[1], bytesAndStatus[2]));
}
@SuppressLint("HandlerLeak") private class MyHandler extends Handler { @Override
public void handleMessage(Message msg) { super.handleMessage(msg);
switch (msg.what) { case 0:
int status = (Integer) msg.obj;
if (isDownloading(status)) { downloadProgress.setVisibility(View.VISIBLE);
downloadProgress.setMax(0);
downloadProgress.setProgress(0);
downloadButton.setVisibility(View.GONE);
downloadSize.setVisibility(View.VISIBLE);
downloadPrecent.setVisibility(View.VISIBLE);
downloadCancel.setVisibility(View.VISIBLE);
if (msg.arg2 < 0) { downloadProgress.setIndeterminate(true);
downloadPrecent.setText("0%"); downloadSize.setText("0M/0M"); } else { downloadProgress.setIndeterminate(false);
downloadProgress.setMax(msg.arg2);
downloadProgress.setProgress(msg.arg1);
downloadPrecent.setText(getNotiPercent(msg.arg1,
msg.arg2));
downloadSize.setText(getAppSize(msg.arg1) + "/"
+ getAppSize(msg.arg2));
}
} else { downloadProgress.setVisibility(View.GONE);
downloadProgress.setMax(0);
downloadProgress.setProgress(0);
downloadButton.setVisibility(View.VISIBLE);
downloadSize.setVisibility(View.GONE);
downloadPrecent.setVisibility(View.GONE);
downloadCancel.setVisibility(View.GONE);
if (status == DownloadManager.STATUS_FAILED) { downloadButton
.setText(getString(R.string.app_status_download_fail));
} else if (status == DownloadManager.STATUS_SUCCESSFUL) { downloadButton
.setText(getString(R.string.app_status_downloaded));
} else { downloadButton
.setText(getString(R.string.app_status_download));
}
}
break;
}
}
}
static final DecimalFormat DOUBLE_DECIMAL_FORMAT = new DecimalFormat("0.##"); public static final int MB_2_BYTE = 1024 * 1024;
public static final int KB_2_BYTE = 1024;
/**
* @param size
* @return
*/
public static CharSequence getAppSize(long size) { if (size <= 0) { return "0M";
}
if (size >= MB_2_BYTE) { return new StringBuilder(16).append(
DOUBLE_DECIMAL_FORMAT.format((double) size / MB_2_BYTE))
.append("M"); } else if (size >= KB_2_BYTE) { return new StringBuilder(16).append(
DOUBLE_DECIMAL_FORMAT.format((double) size / KB_2_BYTE))
.append("K"); } else { return size + "B";
}
}
public static String getNotiPercent(long progress, long max) { int rate = 0;
if (progress <= 0 || max <= 0) { rate = 0;
} else if (progress > max) { rate = 100;
} else { rate = (int) ((double) progress / max * 100);
}
return new StringBuilder(16).append(rate).append("%").toString(); }
public static boolean isDownloading(int downloadManagerStatus) { return downloadManagerStatus == DownloadManager.STATUS_RUNNING
|| downloadManagerStatus == DownloadManager.STATUS_PAUSED
|| downloadManagerStatus == DownloadManager.STATUS_PENDING;
}
}
以及自定义的 DownloadManagerPro 和 PreferencesUtils 类，代码如下所示：
package com.example.download.utils;
import java.lang.reflect.Method;
import android.app.DownloadManager;
import android.app.DownloadManager.Request;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
/**
* DownloadManagerPro
*/
public class DownloadManagerPro { public static final Uri CONTENT_URI = Uri
.parse("content://downloads/my_downloads"); /** represents downloaded file above api 11 **/
public static final String COLUMN_LOCAL_FILENAME = "local_filename";
/** represents downloaded file below api 11 **/
public static final String COLUMN_LOCAL_URI = "local_uri";
public static final String METHOD_NAME_PAUSE_DOWNLOAD = "pauseDownload";
public static final String METHOD_NAME_RESUME_DOWNLOAD = "resumeDownload";
private static boolean isInitPauseDownload = false;
private static boolean isInitResumeDownload = false;
private static Method pauseDownload = null;
private static Method resumeDownload = null;
private DownloadManager downloadManager;
public DownloadManagerPro(DownloadManager downloadManager) { this.downloadManager = downloadManager;
}
/**
* get download status
*
* @param downloadId
* @return
*/
public int getStatusById(long downloadId) { return getInt(downloadId, DownloadManager.COLUMN_STATUS);
}
/**
* get downloaded byte, total byte
*
* @param downloadId
* @return a int array with two elements
*
*
* -1.
*
*
*/
public int[] getDownloadBytes(long downloadId) { int[] bytesAndStatus = getBytesAndStatus(downloadId);
return new int[] { bytesAndStatus[0], bytesAndStatus[1] }; }
/**
* get downloaded byte, total byte and download status
*
* @param downloadId
* @return a int array with three elements
*
*
* -1.
*
*
* 0.
*
*/
public int[] getBytesAndStatus(long downloadId) { int[] bytesAndStatus = new int[] { -1, -1, 0 }; DownloadManager.Query query = new DownloadManager.Query()
.setFilterById(downloadId);
Cursor c = null;
try { c = downloadManager.query(query);
if (c != null && c.moveToFirst()) { bytesAndStatus[0] = c
.getInt(c
.getColumnIndexOrThrow(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR));
bytesAndStatus[1] = c
.getInt(c
.getColumnIndexOrThrow(DownloadManager.COLUMN_TOTAL_SIZE_BYTES));
bytesAndStatus[2] = c.getInt(c
.getColumnIndex(DownloadManager.COLUMN_STATUS));
}
} finally { if (c != null) { c.close();
}
}
return bytesAndStatus;
}
/**
* pause download
*
* @param ids
* the IDs of the downloads to be paused
* @return the number of downloads actually paused, -1 if exception or
* method not exist
*/
public int pauseDownload(long... ids) { initPauseMethod();
if (pauseDownload == null) { return -1;
}
try { return ((Integer) pauseDownload.invoke(downloadManager, ids))
.intValue();
} catch (Exception e) { /**
* accept all exception, include ClassNotFoundException,
* NoSuchMethodException, InvocationTargetException,
* NullPointException
*/
e.printStackTrace();
}
return -1;
}
/**
* resume download
*
* @param ids
* the IDs of the downloads to be resumed
* @return the number of downloads actually resumed, -1 if exception or
* method not exist
*/
public int resumeDownload(long... ids) { initResumeMethod();
if (resumeDownload == null) { return -1;
}
try { return ((Integer) resumeDownload.invoke(downloadManager, ids))
.intValue();
} catch (Exception e) { /**
* accept all exception, include ClassNotFoundException,
* NoSuchMethodException, InvocationTargetException,
* NullPointException
*/
e.printStackTrace();
}
return -1;
}
/**
* whether exist pauseDownload and resumeDownload method in
* {@link DownloadManager} *
* @return
*/
public static boolean isExistPauseAndResumeMethod() { initPauseMethod();
initResumeMethod();
return pauseDownload != null && resumeDownload != null;
}
private static void initPauseMethod() { if (isInitPauseDownload) { return;
}
isInitPauseDownload = true;
try { pauseDownload = DownloadManager.class.getMethod(
METHOD_NAME_PAUSE_DOWNLOAD, long[].class);
} catch (Exception e) { // accept all exception
e.printStackTrace();
}
}
private static void initResumeMethod() { if (isInitResumeDownload) { return;
}
isInitResumeDownload = true;
try { resumeDownload = DownloadManager.class.getMethod(
METHOD_NAME_RESUME_DOWNLOAD, long[].class);
} catch (Exception e) { // accept all exception
e.printStackTrace();
}
}
/**
* get download file name
*
* @param downloadId
* @return
*/
public String getFileName(long downloadId) { return getString(
downloadId,
(Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB ? COLUMN_LOCAL_URI
: COLUMN_LOCAL_FILENAME));
}
/**
* get download uri
*
* @param downloadId
* @return
*/
public String getUri(long downloadId) { return getString(downloadId, DownloadManager.COLUMN_URI);
}
/**
* get failed code or paused reason
*
* @param downloadId
* @return
*
* {@link DownloadManager#STATUS_PAUSED}, return * {@link #getPausedReason(long)} *
* {@link DownloadManager#STATUS_FAILED}, return * {@link #getErrorCode(long)} *
* {@link DownloadManager#STATUS_PAUSED} nor * {@link DownloadManager#STATUS_FAILED}, return 0 *
*/
public int getReason(long downloadId) { return getInt(downloadId, DownloadManager.COLUMN_REASON);
}
/**
* get paused reason
*
* @param downloadId
* @return
*
* {@link DownloadManager#STATUS_PAUSED}, return one of * {@link DownloadManager#PAUSED_WAITING_TO_RETRY} * {@link DownloadManager#PAUSED_WAITING_FOR_NETWORK} * {@link DownloadManager#PAUSED_QUEUED_FOR_WIFI} * {@link DownloadManager#PAUSED_UNKNOWN} *
*
*/
public int getPausedReason(long downloadId) { return getInt(downloadId, DownloadManager.COLUMN_REASON);
}
/**
* get failed error code
*
* @param downloadId
* @return one of {@link DownloadManager#ERROR_*} */
public int getErrorCode(long downloadId) { return getInt(downloadId, DownloadManager.COLUMN_REASON);
}
public static class RequestPro extends DownloadManager.Request { public static final String METHOD_NAME_SET_NOTI_CLASS = "setNotiClass";
public static final String METHOD_NAME_SET_NOTI_EXTRAS = "setNotiExtras";
private static boolean isInitNotiClass = false;
private static boolean isInitNotiExtras = false;
private static Method setNotiClass = null;
private static Method setNotiExtras = null;
/**
* @param uri
* the HTTP URI to download.
*/
public RequestPro(Uri uri) { super(uri);
}
/**
* set noti class, only init once
*
* @param className
* full class name
*/
public void setNotiClass(String className) { synchronized (this) { if (!isInitNotiClass) { isInitNotiClass = true;
try { setNotiClass = Request.class.getMethod(
METHOD_NAME_SET_NOTI_CLASS, CharSequence.class);
} catch (Exception e) { // accept all exception
e.printStackTrace();
}
}
}
if (setNotiClass != null) { try { setNotiClass.invoke(this, className);
} catch (Exception e) { /**
* accept all exception, include ClassNotFoundException,
* NoSuchMethodException, InvocationTargetException,
* NullPointException
*/
e.printStackTrace();
}
}
}
/**
* set noti extras, only init once
*
* @param extras
*/
public void setNotiExtras(String extras) { synchronized (this) { if (!isInitNotiExtras) { isInitNotiExtras = true;
try { setNotiExtras = Request.class
.getMethod(METHOD_NAME_SET_NOTI_EXTRAS,
CharSequence.class);
} catch (Exception e) { // accept all exception
e.printStackTrace();
}
}
}
if (setNotiExtras != null) { try { setNotiExtras.invoke(this, extras);
} catch (Exception e) { /**
* accept all exception, include ClassNotFoundException,
* NoSuchMethodException, InvocationTargetException,
* NullPointException
*/
e.printStackTrace();
}
}
}
}
/**
* get string column
*
* @param downloadId
* @param columnName
* @return
*/
private String getString(long downloadId, String columnName) { DownloadManager.Query query = new DownloadManager.Query()
.setFilterById(downloadId);
String result = null;
Cursor c = null;
try { c = downloadManager.query(query);
if (c != null && c.moveToFirst()) { result = c.getString(c.getColumnIndex(columnName));
}
} finally { if (c != null) { c.close();
}
}
return result;
}
/**
* get int column
*
* @param downloadId
* @param columnName
* @return
*/
private int getInt(long downloadId, String columnName) { DownloadManager.Query query = new DownloadManager.Query()
.setFilterById(downloadId);
int result = -1;
Cursor c = null;
try { c = downloadManager.query(query);
if (c != null && c.moveToFirst()) { result = c.getInt(c.getColumnIndex(columnName));
}
} finally { if (c != null) { c.close();
}
}
return result;
}
}
package com.example.download.utils;
import android.content.Context;
import android.content.SharedPreferences;
/**
* PreferencesUtils, easy to get or put data
*/
public class PreferencesUtils { public static String PREFERENCE_NAME = "TrineaAndroidCommon";
/**
* put string preferences
*
* @param context
* @param key
* The name of the preference to modify
* @param value
* The new value for the preference
* @return True if the new values were successfully written to persistent
* storage.
*/
public static boolean putString(Context context, String key, String value) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = settings.edit();
editor.putString(key, value);
return editor.commit();
}
/**
* get string preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @return The preference value if it exists, or null. Throws
* ClassCastException if there is a preference with this name that
* is not a string
* @see #getString(Context, String, String)
*/
public static String getString(Context context, String key) { return getString(context, key, null);
}
/**
* get string preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @param defaultValue
* Value to return if this preference does not exist
* @return The preference value if it exists, or defValue. Throws
* ClassCastException if there is a preference with this name that
* is not a string
*/
public static String getString(Context context, String key,
String defaultValue) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
return settings.getString(key, defaultValue);
}
/**
* put int preferences
*
* @param context
* @param key
* The name of the preference to modify
* @param value
* The new value for the preference
* @return True if the new values were successfully written to persistent
* storage.
*/
public static boolean putInt(Context context, String key, int value) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = settings.edit();
editor.putInt(key, value);
return editor.commit();
}
/**
* get int preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @return The preference value if it exists, or -1. Throws
* ClassCastException if there is a preference with this name that
* is not a int
* @see #getInt(Context, String, int)
*/
public static int getInt(Context context, String key) { return getInt(context, key, -1);
}
/**
* get int preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @param defaultValue
* Value to return if this preference does not exist
* @return The preference value if it exists, or defValue. Throws
* ClassCastException if there is a preference with this name that
* is not a int
*/
public static int getInt(Context context, String key, int defaultValue) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
return settings.getInt(key, defaultValue);
}
/**
* put long preferences
*
* @param context
* @param key
* The name of the preference to modify
* @param value
* The new value for the preference
* @return True if the new values were successfully written to persistent
* storage.
*/
public static boolean putLong(Context context, String key, long value) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = settings.edit();
editor.putLong(key, value);
return editor.commit();
}
/**
* get long preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @return The preference value if it exists, or -1. Throws
* ClassCastException if there is a preference with this name that
* is not a long
* @see #getLong(Context, String, long)
*/
public static long getLong(Context context, String key) { return getLong(context, key, -1);
}
/**
* get long preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @param defaultValue
* Value to return if this preference does not exist
* @return The preference value if it exists, or defValue. Throws
* ClassCastException if there is a preference with this name that
* is not a long
*/
public static long getLong(Context context, String key, long defaultValue) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
return settings.getLong(key, defaultValue);
}
/**
* put float preferences
*
* @param context
* @param key
* The name of the preference to modify
* @param value
* The new value for the preference
* @return True if the new values were successfully written to persistent
* storage.
*/
public static boolean putFloat(Context context, String key, float value) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = settings.edit();
editor.putFloat(key, value);
return editor.commit();
}
/**
* get float preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @return The preference value if it exists, or -1. Throws
* ClassCastException if there is a preference with this name that
* is not a float
* @see #getFloat(Context, String, float)
*/
public static float getFloat(Context context, String key) { return getFloat(context, key, -1);
}
/**
* get float preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @param defaultValue
* Value to return if this preference does not exist
* @return The preference value if it exists, or defValue. Throws
* ClassCastException if there is a preference with this name that
* is not a float
*/
public static float getFloat(Context context, String key, float defaultValue) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
return settings.getFloat(key, defaultValue);
}
/**
* put boolean preferences
*
* @param context
* @param key
* The name of the preference to modify
* @param value
* The new value for the preference
* @return True if the new values were successfully written to persistent
* storage.
*/
public static boolean putBoolean(Context context, String key, boolean value) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = settings.edit();
editor.putBoolean(key, value);
return editor.commit();
}
/**
* get boolean preferences, default is false
*
* @param context
* @param key
* The name of the preference to retrieve
* @return The preference value if it exists, or false. Throws
* ClassCastException if there is a preference with this name that
* is not a boolean
* @see #getBoolean(Context, String, boolean)
*/
public static boolean getBoolean(Context context, String key) { return getBoolean(context, key, false);
}
/**
* get boolean preferences
*
* @param context
* @param key
* The name of the preference to retrieve
* @param defaultValue
* Value to return if this preference does not exist
* @return The preference value if it exists, or defValue. Throws
* ClassCastException if there is a preference with this name that
* is not a boolean
*/
public static boolean getBoolean(Context context, String key,
boolean defaultValue) { SharedPreferences settings = context.getSharedPreferences(
PREFERENCE_NAME, Context.MODE_PRIVATE);
return settings.getBoolean(key, defaultValue);
}
}
参考资料