Android 核心技术

来源：互联网发布：sniffer linux 编辑：程序博客网时间：2024/06/04 19:00

1.service组件后台服务：service一般有activity启动，service具有自己较长的生命周期，当activity结束后，service不会结束，当service自己的生命周期结束时才会结束。

service的两种那个启动方式：startservice，bindservice

service后台服务的用法：

1.都需要在Androidmanifest.xml中声明，格式如下

2.需要子类继承service，并需要重写onbind(),oncreate(),onstratcommand(),ondestory()四个方法。

3.在其他activity中启动service后台服务：直接调用startservice(Intent)即可，

停止service服务调用stoopservice(Intent)

如下:

 Intent serviceIntent = new Intent(MainActivity.this, MyService.class);24                 startService(serviceIntent);

其中MyService就是继承了service的子类。

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自定义service服务调用代码：

activity调用：

button0.setOnClickListener(new View.OnClickListener() {    @Override    public void onClick(View v) {        Intent intent=new Intent(MainActivity.this, MyService.class);        intent.putExtra("msg","启动service成功");        intent.setAction("MyService");        startService(intent);    }});

androidifest.xml注册：

<service android:name="com.android.zhujian.MyService">    <intent-filter>        <action android:name="com.android.zhujian"></action>    </intent-filter></service>

布局：

<Button android:layout_width="match_parent"        android:id="@+id/btn0"        android:text="自定义启动service"        android:layout_height="50dp" tools:ignore="HardcodedText"/>

继承service：

package com.android.zhujian;import android.app.Service;import android.content.Intent;import android.os.IBinder;import android.widget.Toast;/** * Created by Administrator on 2017/7/26. */public class MyService extends Service {    @Override    public IBinder onBind(Intent intent) {        Toast.makeText(getBaseContext(),"onBind",Toast.LENGTH_LONG).show();        return null;    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Toast.makeText(getBaseContext(),intent.getStringExtra("msg"),Toast.LENGTH_LONG).show();        return super.onStartCommand(intent, flags, startId);    }    @Override    public void onCreate() {        super.onCreate();        Toast.makeText(getBaseContext(),"oncreate",Toast.LENGTH_LONG).show();    }    @Override    public void onDestroy() {        super.onDestroy();        Toast.makeText(getBaseContext(),"ondestory",Toast.LENGTH_LONG).show();    }}
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2.BroadcastReceiver组件广播发送与接收实现：

第一步：需要new一个BroadcastReceiver并重写onreceive方法

第二步：需要在其他activity中注册广播：直接调用registerReceiver(BroadcastReceiver,IntentFilter)

其中的braodcasrreceiver中的onreceive()就是接收广播

第三步：发送广播：直接调用sendBroadCast(Intent)

第四步：在androidifest.xml中注册

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.byread" android:versionCode="1" android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".MainActivity" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".StaticReceiver">
<intent-filter>
<action android:name="包名" />
</intent-filter>
</receiver>
<receiver android:name=".SystemReceiver">
<intent-filter>
<action android:name="android.intent.action.BATTERY_LOW" />
</intent-filter>
</receiver>
</application>
</manifest>

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代码注册：

package com.example.administrator.andriod_four_zujian;import android.content.BroadcastReceiver;import android.content.Intent;import android.content.IntentFilter;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.util.Log;import android.view.View;import android.widget.Button;import com.android.zhujian.StaticBroadCast;public class MainActivity extends AppCompatActivity {    private Button button;    private BroadcastReceiver  broadcastReceiver=new StaticBroadCast();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        button=(Button)findViewById(R.id.btn1);        button.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Log.i("info", "onClick: "+13);                Intent intent=new Intent();                intent.setAction("staticBroadCast");                intent.putExtra("msg","静态广播接收成功");                sendBroadcast(intent);            }        });    }    @Override    protected void onStart() {        super.onStart();        IntentFilter intentFilter=new IntentFilter();        intentFilter.addAction("staticBroadCast");        registerReceiver(broadcastReceiver,intentFilter);    }}

package com.android.zhujian;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.widget.Toast;/** * Created by Administrator on 2017/7/26. */public class StaticBroadCast extends BroadcastReceiver{    @Override    public void onReceive(Context context, Intent intent) {        if(intent.getAction().equals("staticBroadCast")){           String msg= intent.getStringExtra("msg");            Toast.makeText(context,msg,Toast.LENGTH_LONG).show();        }    }}

<?xml version="1.0" encoding="utf-8"?><RelativeLayout    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.administrator.andriod_four_zujian.MainActivity">    <Button android:layout_width="match_parent"            android:id="@+id/btn1"            android:text="自定义静态注册发送广播"            android:layout_height="wrap_content" tools:ignore="HardcodedText"/></RelativeLayout>

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