这篇文章主要介绍了Android监听Home键和Back键的区别介绍,本文还同时给出了Home键监听的实现代码,需要的朋友可以参考下
一:Android 中Home键监听和Back键监听的区别:
(1).在Android中,当按下Home键的时候,默认情况下Stop前台的Activity,即Activity设置成停止状态【onStop()】,而不是销毁状态【onDestory()】。如果再次启动该Activity,不是调用onCreate()方法,而是调用onSavedInstanceState方法。则是从onRestart()开始-onStart()-onResume()。
(2).当按下back键则不同,back键默认finish前台的activity,即activity的状态为onDestory为止,再次启动该activity则从onCreate开始,不会调用onSavedInstanceState方法。
总而言之:按下Home键会返回桌面,而back则会返回前一个activity。
在这里Back键的实现方法就不赘述了,主要讲解一下Home键的实现方式吧。以下是我找的参考资料自己思考的。请大家给出建议。
Home键监听的实现方法:
(1).在onResum里面注册广播,OnPause里面注销广播。
(2).在广播中拦截Intent.ACTION_CLOSE_SYSTEM_DIALOGS 这个Action ,通过获取Reason字段 来判断长按 还是单击Home键。
代码如下:
(1).Home键监听封装类:
- 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键监听封装
- *
- * @author way
- *
- */
- public class HomeWatcher {
- // 回调接口
- public interface OnHomePressedListener {
- public void onHomePressed();
- public void onHomeLongPressed();
- }
- private static final String TAG = "HomeWatcher";
- /** 上下文 */
- private Context mContext;
- /** 过滤器 */
- private IntentFilter mFilter;
- /** 接口 */
- private OnHomePressedListener mListener;
- /** 广播接收者 */
- private InnerRecevier mRecevier;
- public HomeWatcher(Context context) {
- mContext = context;
- mRecevier = new InnerRecevier();
- mFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
- }
- /**
- * 设置监听
- *
- * @param listener
- */
- public void setOnHomePressedListener(OnHomePressedListener listener) {
- mListener = listener;
- }
- /**
- * 开始监听,注册广播
- */
- public void startWatch() {
- if (mRecevier != null) {
- mContext.registerReceiver(mRecevier, mFilter);
- }
- }
- /**
- * 停止监听,注销广播
- */
- public void stopWatch() {
- if (mRecevier != null) {
- mContext.unregisterReceiver(mRecevier);
- }
- }
- /**
- * 广播接收者
- */
- 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键
- mListener.onHomePressed();
- } else if (reason
- .equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) {
- // 长按home键
- mListener.onHomeLongPressed();
- }
- }
- }
- }
- }
- }
- }
(2).MainActivity类:
- 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);
- // 注册广播
- mHomeWatcher.startWatch();
- super.onResume();
- }
- @Override
- protected void onPause() {
- mHomeWatcher.setOnHomePressedListener(null);
- // 注销广播
- mHomeWatcher.stopWatch();
- super.onPause();
- }
- @Override
- public void onHomePressed() {
- // TODO
- Toast.makeText(this, "短按Home键,实现自己的逻辑", Toast.LENGTH_SHORT).show();
- }
- @Override
- public void onHomeLongPressed() {
- // TODO
- Toast.makeText(this, "长按Home键,实现自己的逻辑", Toast.LENGTH_SHORT).show();
- }
- @Override
- public boolean onKeyDown(int keyCode, KeyEvent event) {
- if ((keyCode == KeyEvent.KEYCODE_BACK)) {
- System.out.println("按下了back键 onKeyDown()");
- return false;
- } else {
- return super.onKeyDown(keyCode, event);
- }
- }
- @Override
- public void onBackPressed() {
- // super.onBackPressed()会自动调用finish()方法,关闭
- super.onBackPressed();
- }
- }
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