7.Android之评分条RatingBar和拖动条SeekBar学习

评分条RatingBar和拖动条SeekBar很常见，今天来学习下。

(1)RatingBar评分条

如图:

<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="com.example.ratingbar.MainActivity" >

<RatingBar
android:id="@+id/ratingBar1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="22dp"
android:layout_marginTop="25dp" />

</RelativeLayout>

RatingBar监听事件：public void setOnRatingBarChangeListener (RatingBar.OnRatingBarChangeListener listener)

(2)拖动他SeekBar使用

首先从工具中拖入一个SeekBar和两个TextView，如图：



代码如下：

<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="com.example.ratingbar.MainActivity" >

<SeekBar
android:id="@+id/seekBar1"
android:max="100"
android:progress="50"
android:secondaryProgress="75"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="35dp" />

<TextView
android:id="@+id/info1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/seekBar1"
android:layout_below="@+id/seekBar1"
android:layout_marginTop="24dp"/>

<TextView
android:id="@+id/info2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/info1"
android:layout_below="@+id/info1"
android:layout_marginTop="32dp"/>

</RelativeLayout>

然后我们实现OnSeekBarChangeListener接口：public class MainActivity extends Activity implements OnSeekBarChangeListener{...} ,此接口共需要监听三个事件，分别是：
数值改变（onProgressChanged）
开始拖动（onStartTrackingTouch）
停止拖动（onStopTrackingTouch）

完整代码如下：

package com.example.ratingbar;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;

//实现OnSeekBarChangeListener接口
public class MainActivity extends Activity implements OnSeekBarChangeListener {

private SeekBar sbVolumer=null;
private TextView info1=null;
private TextView info2=null;

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

sbVolumer = (SeekBar) findViewById(R.id.seekBar1);
sbVolumer.setOnSeekBarChangeListener(this);
info1 = (TextView) findViewById(R.id.info1);
info2 = (TextView) findViewById(R.id.info2);
}

@Override
public 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;
}

@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);
}

@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {

info1.setText("当前值： " + progress);
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {

info2.setText("正在改变当前值");
}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
info2.setText("停止拖动");
}
}

运行效果：