Handler的使用

常用方法

post(Runnable runnable)　　启动线程

removeCallbacks(Runnable runnable)　　取消线程

postDelayed(Runnable runnable,int time)　　延时启动线程

例、应用启动的欢迎界面

XML

首先是welcome.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <RelativeLayout
 3     android:layout_width="fill_parent"
 4     android:layout_height="fill_parent"
 5     xmlns:android="http://schemas.android.com/apk/res/android">
 6 
 7     <ImageView
 8         android:layout_width="wrap_content"
 9         android:layout_height="wrap_content"
10         android:id="@+id/imageView"
11         android:layout_alignParentLeft="true"
12         android:layout_alignParentStart="true"
13         android:layout_alignParentTop="true"
14         android:layout_alignParentBottom="true"
15         android:src="@drawable/music"
16         android:layout_alignParentRight="true"
17         android:layout_alignParentEnd="true" />
18 
19 </RelativeLayout>

然后是main.xml

 1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:paddingLeft="@dimen/activity_horizontal_margin"
 6     android:paddingRight="@dimen/activity_horizontal_margin"
 7     android:paddingTop="@dimen/activity_vertical_margin"
 8     android:paddingBottom="@dimen/activity_vertical_margin"
 9     tools:context=".MyActivity">
10 
11     <TextView
12         android:text="@string/hello_world"
13         android:layout_width="wrap_content"
14         android:layout_height="wrap_content" />
15 
16 </RelativeLayout>

JAVA

welcome.java

class="brush:java;gutter:true;">import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.view.Window;
import android.widget.ImageView;

public class welcome extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.welcome);
        new  Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                Intent mainIntent = new Intent(welcome.this,MyActivity.class);
                welcome.this.startActivity(mainIntent);
                welcome.this.finish();
            }
        },3000);
    }
}

　　这里使用requestWindowFeature(Window.FEATURE_NO_TITLE)将标题栏隐藏。创建一个子线程，延时3秒跳转的下一个Activity。

MyActivity.java

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;


public class MyActivity extends Activity {

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


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.my, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}