Android學習筆記之ProgressBar案例分析

標籤：android學習筆記之progress   asynctask   android   progressbar   

（1）

<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=".MainActivity" >    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="進度條的使用：" />    <ProgressBar        android:id="@+id/progressBar1"        style="?android:attr/progressBarStyleHorizontal"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/button1"        android:layout_alignRight="@+id/button1"        android:layout_below="@+id/textView1"        android:layout_marginTop="30dp" />    <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/textView1"        android:layout_below="@+id/progressBar1"        android:layout_marginLeft="74dp"        android:layout_marginTop="146dp"        android:text="下載圖片" /></RelativeLayout>

（2）

package com.example.progressbar;import android.app.Activity;import android.os.AsyncTask;import android.os.Bundle;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.ProgressBar;public class MainActivity extends Activity {private Button button1;private ProgressBar progressBar1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);button1 = (Button) this.findViewById(R.id.button1);progressBar1 = (ProgressBar) this.findViewById(R.id.progressBar1);progressBar1.setMax(100);// 設定最大值為100button1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {new MyTask().execute();}});}class MyTask extends AsyncTask<Void, Integer, Void> {@Overrideprotected void onProgressUpdate(Integer... values) {super.onProgressUpdate(values);progressBar1.setProgress(values[0]);}@Overrideprotected Void doInBackground(Void... params) {int i = 1;while (i <= 100) {try {Thread.sleep(500);} catch (Exception e) {// TODO: handle exception}publishProgress(i);i++;}return null;}}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}

（3）示範效果

Android學習筆記之ProgressBar案例分析