学步园

一. 初步认识

src

package cn.android.lyj;

import android.app.Activity;
import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.TextView;

public class Activity_01 extends Activity implements SeekBar.OnSeekBarChangeListener {
    
    SeekBar mSeekBar;
    TextView mProgressText;
    TextView mTrackingText;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);
        
        mSeekBar = (SeekBar)findViewById(R.id.seek);
        mSeekBar.setOnSeekBarChangeListener(this);
        mProgressText = (TextView)findViewById(R.id.progress);
        mTrackingText = (TextView)findViewById(R.id.tracking);
    }

    //进度条改变事件
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromTouch) {
        mProgressText.setText(progress + " " + 
                getString(R.string.seekbar_from_touch) + "=" + fromTouch);
    }

    //接触拖动条事件
    public void onStartTrackingTouch(SeekBar seekBar) {
        mTrackingText.setText(getString(R.string.seekbar_tracking_on));
    }

    //离开接触条事件
    public void onStopTrackingTouch(SeekBar seekBar) {
        mTrackingText.setText(getString(R.string.seekbar_tracking_off));
    }
}

main.xml

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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <SeekBar android:id="@+id/seek"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="100"
        android:progress="50"
        android:secondaryProgress="75" />

    <TextView android:id="@+id/progress"
       	android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView android:id="@+id/tracking"
       	android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

strings.xml

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

    <string name="seekbar_tracking_on">Tracking on</string>
    <string name="seekbar_tracking_off">Tracking off</string>
    <string name="seekbar_from_touch">from touch</string>
    <string name="app_name">SeekBar</string>

</resources>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.android.lyj"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="10" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".Activity_01" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

二. 运行结果

启动时在50

拖动到25