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Android監(jiān)聽(tīng)Home鍵和Back鍵的區(qū)別介紹

更新時(shí)間：2015年06月06日 10:16:40 投稿：junjie

這篇文章主要介紹了Android監(jiān)聽(tīng)Home鍵和Back鍵的區(qū)別介紹,本文還同時(shí)給出了Home鍵監(jiān)聽(tīng)的實(shí)現(xiàn)代碼,需要的朋友可以參考下

一：Android 中Home鍵監(jiān)聽(tīng)和Back鍵監(jiān)聽(tīng)的區(qū)別：

(1).在A(yíng)ndroid中，當(dāng)按下Home鍵的時(shí)候，默認(rèn)情況下Stop前臺(tái)的Activity，即Activity設(shè)置成停止?fàn)顟B(tài)【onStop()】，而不是銷(xiāo)毀狀態(tài)【onDestory()】。如果再次啟動(dòng)該Activity，不是調(diào)用onCreate()方法，而是調(diào)用onSavedInstanceState方法。則是從onRestart()開(kāi)始-onStart()-onResume()。
(2).當(dāng)按下back鍵則不同，back鍵默認(rèn)finish前臺(tái)的activity，即activity的狀態(tài)為onDestory為止，再次啟動(dòng)該activity則從onCreate開(kāi)始，不會(huì)調(diào)用onSavedInstanceState方法。
總而言之：按下Home鍵會(huì)返回桌面，而back則會(huì)返回前一個(gè)activity。

在這里Back鍵的實(shí)現(xiàn)方法就不贅述了，主要講解一下Home鍵的實(shí)現(xiàn)方式吧。以下是我找的參考資料自己思考的。請(qǐng)大家給出建議。
Home鍵監(jiān)聽(tīng)的實(shí)現(xiàn)方法：
(1).在onResum里面注冊(cè)廣播，OnPause里面注銷(xiāo)廣播。
(2).在廣播中攔截Intent.ACTION_CLOSE_SYSTEM_DIALOGS 這個(gè)Action ，通過(guò)獲取Reason字段來(lái)判斷長(zhǎng)按還是單擊Home鍵。
代碼如下：

(1).Home鍵監(jiān)聽(tīng)封裝類(lèi)：

package com.scd.homewatcher.util;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;

/**
 * Home鍵監(jiān)聽(tīng)封裝
 * 
 * @author way
 * 
 */
public class HomeWatcher {

  // 回調(diào)接口
  public interface OnHomePressedListener {

    public void onHomePressed();

    public void onHomeLongPressed();
  }

  private static final String TAG = "HomeWatcher";
  /** 上下文 */
  private Context mContext;
  /** 過(guò)濾器 */
  private IntentFilter mFilter;
  /** 接口 */
  private OnHomePressedListener mListener;
  /** 廣播接收者 */
  private InnerRecevier mRecevier;

  public HomeWatcher(Context context) {
    mContext = context;
    mRecevier = new InnerRecevier();
    mFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
  }

  /**
   * 設(shè)置監(jiān)聽(tīng)
   * 
   * @param listener
   */
  public void setOnHomePressedListener(OnHomePressedListener listener) {
    mListener = listener;
  }

  /**
   * 開(kāi)始監(jiān)聽(tīng)，注冊(cè)廣播
   */
  public void startWatch() {
    if (mRecevier != null) {
      mContext.registerReceiver(mRecevier, mFilter);
    }
  }

  /**
   * 停止監(jiān)聽(tīng)，注銷(xiāo)廣播
   */
  public void stopWatch() {
    if (mRecevier != null) {
      mContext.unregisterReceiver(mRecevier);
    }
  }

  /**
   * 廣播接收者
   */
  private class InnerRecevier extends BroadcastReceiver {
    final String SYSTEM_DIALOG_REASON_KEY = "reason";
    final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions";
    final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";
    final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";

    @Override
    public void onReceive(Context context, Intent intent) {
      String action = intent.getAction();
      if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
        String reason = intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
        if (reason != null) {
          Log.i(TAG, "action:" + action + ",reason:" + reason);
          if (mListener != null) {
            if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) {
              // 短按home鍵
              mListener.onHomePressed();
            } else if (reason
                .equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) {
              // 長(zhǎng)按home鍵
              mListener.onHomeLongPressed();
            }
          }
        }
      }
    }
  }
}

(2).MainActivity類(lèi)：

package com.scd.homewatcher;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.Toast;

import com.scd.homewatcher.util.HomeWatcher;
import com.scd.homewatcher.util.HomeWatcher.OnHomePressedListener;

public class MainActivity extends Activity implements OnHomePressedListener {
  private HomeWatcher mHomeWatcher;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

  }

  @Override
  protected void onResume() {
    mHomeWatcher = new HomeWatcher(this);
    mHomeWatcher.setOnHomePressedListener(this);
    // 注冊(cè)廣播
    mHomeWatcher.startWatch();
    super.onResume();
  }

  @Override
  protected void onPause() {
    mHomeWatcher.setOnHomePressedListener(null);
    // 注銷(xiāo)廣播
    mHomeWatcher.stopWatch();
    super.onPause();
  }

  @Override
  public void onHomePressed() {
    // TODO
    Toast.makeText(this, "短按Home鍵,實(shí)現(xiàn)自己的邏輯", Toast.LENGTH_SHORT).show();

  }

  @Override
  public void onHomeLongPressed() {
    // TODO
    Toast.makeText(this, "長(zhǎng)按Home鍵,實(shí)現(xiàn)自己的邏輯", Toast.LENGTH_SHORT).show();

  }

  @Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
    if ((keyCode == KeyEvent.KEYCODE_BACK)) {
      System.out.println("按下了back鍵 onKeyDown()");
      return false;
    } else {
      return super.onKeyDown(keyCode, event);
    }

  }

  @Override
  public void onBackPressed() {
    // super.onBackPressed()會(huì)自動(dòng)調(diào)用finish()方法,關(guān)閉
    super.onBackPressed();
  }

}

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