Handler与ProgressBar 例子

MainActivity

package ray.com.hander_progressbar;import android.os.Handler;import android.os.Message;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.ProgressBar;public class MainActivity extends AppCompatActivity {    private ProgressBar proBar = null;    private Button button = null;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        proBar = (ProgressBar) findViewById(R.id.probar);        button = (Button) findViewById(R.id.button1);        button.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                proBar.setVisibility(View.VISIBLE);                // 防止重复点击post很多线程进去                if (proBar.getProgress() > 0) {                    return;                }                handler.post(runnable);            }        });    }    Handler handler = new Handler() {        @Override        public void handleMessage(Message message) {            proBar.setProgress(message.arg1);            handler.post(runnable);        }    };    Runnable runnable = new Runnable() {        int i = 1;        @Override        public void run() {            i++;            Message message = handler.obtainMessage();            message.arg1 = i;            try {                Thread.sleep(40);            } catch (InterruptedException e) {                e.printStackTrace();            }            handler.sendMessage(message);            if (i > 100) {                handler.removeCallbacks(this);                i = 1;            }        }    };}

activity_main

<?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: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"    tools:context="ray.com.hander_progressbar.MainActivity">    <ProgressBar        android:layout_width="match_parent"        android:layout_height="wrap_content"        style="?android:attr/progressBarStyleHorizontal"        android:id="@+id/probar"        android:visibility="gone"/>    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/button1"        android:layout_centerVertical="true"        android:layout_centerHorizontal="true"        android:text="Start"/></RelativeLayout>