[Android开发常见问题-5] 如何检测耳机的插入状态

近期在研究如何通过耳机进行一些控制操作，自然涉及到如何检测耳机是否插入的状态，经过一番查询和实验，总结如下

1.原理：

其实android系统在耳机插入和拔出的时候都会发送广播，所以我们要想检测耳机的状态只需要注册响应的BroadCastReceiver，对状态进行响应的判断就ok了。

这个广播的名字叫做：android.intent.action.HEADSET_PLUG

注意，在manifest.xml里面要添加响应的权限：

<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

注意，广播要在java文件中动态注册。

2.代码

[java]

/**
* Created By:alex
*/

package com.alex.erji;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends Activity {

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

        //给广播绑定响应的过滤器
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction("android.intent.action.HEADSET_PLUG");
        HeadsetReceiver headsetReceiver = new HeadsetReceiver();
        registerReceiver(headsetReceiver, intentFilter);

    }

    //自己定义的广播接收器
    public class HeadsetReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            if (intent.hasExtra("state")) {
                if (0 == intent.getIntExtra("state", 0)) {
                    Toast.makeText(context, "耳机未插入", Toast.LENGTH_SHORT).show();
                } else if (1 == intent.getIntExtra("state", 0)) {
                    Toast.makeText(context, "耳机已插入", Toast.LENGTH_SHORT).show();
                }
            }

        }
    }
}

/**
* Created By:alex
*/

package com.alex.erji;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends Activity {

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

  //给广播绑定响应的过滤器
  IntentFilter intentFilter = new IntentFilter();
  intentFilter.addAction("android.intent.action.HEADSET_PLUG");
  HeadsetReceiver headsetReceiver = new HeadsetReceiver();
  registerReceiver(headsetReceiver, intentFilter);

}

//自己定义的广播接收器
public class HeadsetReceiver extends BroadcastReceiver {

  @Override
  public void onReceive(Context context, Intent intent) {
   if (intent.hasExtra("state")) {
    if (0 == intent.getIntExtra("state", 0)) {
     Toast.makeText(context, "耳机未插入", Toast.LENGTH_SHORT).show();
    } else if (1 == intent.getIntExtra("state", 0)) {
     Toast.makeText(context, "耳机已插入", Toast.LENGTH_SHORT).show();
    }
   }

}
}
}

正常运行后，插入耳机时会提醒“耳机已插入”，拔出耳机时提醒“耳机未插入”。

补充：移动开发 , Android ,