HandlerCallbackAcitvity.java
package com.jing.example.nknu_.handlercallbackactivity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
public class HandlerCallbackActivity extends AppCompatActivity implements Handler.Callback {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_handler_callback);
}
@Override
public boolean handleMessage(Message msg) {
switch(msg.what){
case 1:
msg.what = 11;
System.out.println("訊息已被處理");
return true;//訊息已被處理，不返回handlerMessage
default:
msg.what = 22;
return false;//訊息未被處理，返回handlerMessage處理
}
}
public void onHandlerCallback(View v){
Handler handler = new Handler(this){
@Override
public void handleMessage(Message msg){
System.out.println("訊息為 " + String.valueOf(msg.what) + "尚未被處理");
}
};
handler.sendEmptyMessage(1);
handler.sendEmptyMessage(2);
}
}
content_handler_callback.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.jing.example.nknu_.handlercallbackactivity.HandlerCallbackActivity"
tools:showIn="@layout/activity_handler_callback">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!"
android:id="@+id/textView" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="@+id/button"
android:layout_below="@+id/textView"
android:layout_toEndOf="@+id/textView"
android:layout_marginTop="173dp"
android:onClick="onHandlerCallback" />
</RelativeLayout>