Android开发之进度条、拖动条、TabHost

进度条(ProgressBar)

进度条可以带给用户良好的体验,Android系统已经为我们提供了ProgressBar类来完成进度条的效果,我们可以很方便的运用该类。其中最常见的两种进度条是“环形进度条”和“水平进度条”,在布局文件中定义两种进度条的方式比较相似,区别是,定义“水平进度条时”需要加上一项属性“style="?android:attr/progressBarStyleHorizontal"”。ProgressBar类

中常用的方法如下:

ProgressBar.setMax(int max);设置总长度为100

ProgressBar.setProgress(int progress);设置已经开启长度为0,假设设置为50,进度条将进行到一半停止。

实例:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical" >

 

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:text="进度条演示" />

 

    <ProgressBar

        android:id="@+id/probarId1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:max="1000"

        android:progress="100" />

 

    <ProgressBar

        android:id="@+id/probarId2"

        style="@android:style/Widget.ProgressBar.Horizontal"

       android:layout_marginTop="50dp"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:max="100000"

        android:progress="100"

        android:secondaryProgress="300"

        />

 

</LinearLayout>

////////////////// ProgressBarActivity///////////////////

package cn.class3g.activity;

 

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.util.Log;

import android.widget.ProgressBar;

 

public class ProgressBarActivity extends Activity {

   ProgressBar pro = null;

   int i = 0;

   int proMax = 0;

 

   Handler handler = new Handler();

 

   public void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

      setContentView(R.layout.main);

      findViews();

   }

 

   private void findViews() {

      pro = (ProgressBar) this.findViewById(R.id.probarId2);

      proMax = pro.getMax();

 

      new Thread(new Runnable() {

 

        public void run() {

           while (i < proMax) {

              i=dowork();

              handler.post(new Runnable() {

 

                 public void run() {

                    pro.setProgress(i);

 

                 }

              });

           }

 

        }

 

      }

 

      ).start();

   }

public int dowork(){

   Log.d("tag", String.valueOf(i));

   return i+=1;

}

   /*

    * //不能用

    *

    * @Override public void run() { // TODO Auto-generated method stub while

    * (i++ < proMax) { pro.setProgress(i); try { Thread.sleep(50); } catch

    * (InterruptedException e) { // TODO Auto-generated catch block

    * e.printStackTrace(); } } }

    */

}

拖动条(SeekBar)

进度条只能显示进度,用户不能与程序交互,通过对其操作来改变其值。而拖动条就可以实现此功能。拖动条比较常见,如“千千静听”中的播放进度条就是一个拖动条。Android平台中的SeekBar 是ProgressBar 的间接子类。

SeekBar.getProgress():获取拖动条当前值

调用setOnSeekBarChangeListener() 方法,处理拖动条值变化事件, 把SeekBar.OnSeekBarChangeListener 实例作为参数传入

实例:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

 

    <SeekBar

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:max="1000"

        android:id="@+id/seekbarId"

        />

 

</LinearLayout>

////////////////// SeekBarActivity/////////////////

package cn.class3g.activity;

 

import android.app.Activity;

import android.os.Bundle;

import android.util.Log;

import android.widget.SeekBar;

import android.widget.SeekBar.OnSeekBarChangeListener;

 

public class SeekBarActivity extends Activity implements OnSeekBarChangeListener{

   SeekBar seekbar = null;

   public void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

      setContentView(R.layout.seekbar);

      findViews();

   }

   private void findViews() {

      seekbar = (SeekBar) this.findViewById(R.id.seekbarId);

     

      seekbar.setOnSeekBarChangeListener(this);

   }

   @Override

   public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {

      Log.d("tag","changed:" +String.valueOf(arg0.getProgress()));

     

   }

   @Override

   public void onStartTrackingTouch(SeekBar seekBar) {

      Log.d("tag","start:" +String.valueOf(seekBar.getProgress()));

     

   }

   @Override

   public void onStopTrackingTouch(SeekBar seekBar) {

      Log.d("tag","stop:" +String.valueOf(seekBar.getProgress()));

     

   }

  

}

TabHost

<?xml version="1.0" encoding="utf-8"?>

<TabHost xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent" >

 

    <LinearLayout

        android:id="@+id/tab1"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:orientation="vertical" >

 

 

    <Button

        android:id="@+id/buttonId"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="切换到tab2" />

 

    <ImageView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:src="@drawable/p2"

        android:scaleType="fitCenter"

        android:layout_marginTop="20dp"

        />

  </LinearLayout>

</TabHost>

/////////////// TabHostActivity///////////

package cn.class3g.activity;

 

import android.app.TabActivity;

import android.content.Intent;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TabHost;

 

public class TabHostActivity extends TabActivity {

   TabHost tabHost = null;

 

   public void onCreate(Bundle savedInstanceState) {

      super.onCreate(savedInstanceState);

 

      tabHost = this.getTabHost();

 

      LayoutInflater inflater = LayoutInflater.from(this);

 

      inflater.inflate(R.layout.tabhost, tabHost.getTabContentView(), true);

 

      // tabHost.addTab(tabHost.newTabSpec("tab2").setIndicator(""));

      tabHost.addTab(tabHost.newTabSpec("tab1").setIndicator("切换标签")

           .setContent(R.id.tab1));

      tabHost.addTab(tabHost.newTabSpec("tab2").setIndicator("标签2")

           .setContent(new Intent(this, ProgressBarActivity.class)));

 

      findViews();

   }

 

   private void findViews() {

      Button btn = (Button) this.findViewById(R.id.buttonId);

      btn.setOnClickListener(new OnClickListener() {

 

        @Override

        public void onClick(View v) {

           // tabHost.setCurrentTab(1);

           tabHost.setCurrentTabByTag("tab2");

 

        }

      });

 

   }

}

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