從零開始學android<SeekBar滑動組件.二十二.>

標籤：風飛雪未揚   從零開始學android   seekbar組件的使用   android改變螢幕亮度   

拖動條可以由使用者自己進行手工的調節，例如：當使用者需要調整播放器音量或者是電影的播放進度時都會使用到拖動條，SeekBar類的定義結構如下所示：java.lang.Object   ? android.view.View     ? android.widget.ProgressBar       ? android.widget.AbsSeekBar         ? android.widget.SeekBar常用方法

public SeekBar(Context context)	構造	建立SeekBar類的對象
public void setOnSeekBarChangeListener(SeekBar.OnSeekBarChangeListener l)	普通	設定改變監聽操作
public synchronized void setMax(int max)	普通	設定增長的最大值

public static interface SeekBar.OnSeekBarChangeListener{/** * 開始拖動時觸發操作 * @param seekBar觸發操作的SeekBar組件對象 */ public abstract void onStartTrackingTouch(SeekBar seekBar) ;/**  * @param seekBar觸發操作的SeekBar組件對象 * @param progress當前的進度值 * @param fromUser是否為使用者自己觸發 */ public abstract void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) ;/** * 停止拖動時觸發操作 * @param seekBar觸發操作的SeekBar組件對象 */ public abstract void onStopTrackingTouch(SeekBar seekBar) ;}

基本的使用

xml檔案

<span style="font-size:18px;"><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" >    <SeekBar        android:max="100"        android:progress="30"        android:id="@+id/seekBar1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_alignParentTop="true"        android:layout_marginTop="60dp" />    <TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/seekBar1"        android:layout_below="@+id/seekBar1"        android:layout_marginLeft="28dp"        android:layout_marginTop="32dp"        android:text="seek1"        android:textAppearance="?android:attr/textAppearanceMedium" />    <SeekBar        android:id="@+id/seekBar2"        android:max="100"        android:secondaryProgress="60"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_below="@+id/textView1"        android:layout_marginTop="67dp" />    <TextView        android:id="@+id/textView2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/textView1"        android:layout_below="@+id/seekBar2"        android:layout_marginTop="28dp"        android:text="seek2"        android:textAppearance="?android:attr/textAppearanceMedium" /></RelativeLayout></span>

java檔案

<span style="font-size:18px;">package com.example.seekbar;import android.app.Activity;import android.os.Bundle;import android.widget.SeekBar;import android.widget.SeekBar.OnSeekBarChangeListener;import android.widget.TextView;public class MainActivity extends Activity implements OnSeekBarChangeListener{private TextView textView1,textView2;private SeekBar seekBar1,seekBar2;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        textView1=(TextView)this.findViewById(R.id.textView1);        textView2=(TextView)this.findViewById(R.id.textView2);        seekBar1=(SeekBar)this.findViewById(R.id.seekBar1);        seekBar2=(SeekBar)this.findViewById(R.id.seekBar2);        seekBar1.setOnSeekBarChangeListener(this);        seekBar2.setOnSeekBarChangeListener(this);    }@Overridepublic void onProgressChanged(SeekBar seekBar, int position, boolean flag) {// TODO Auto-generated method stubif (seekBar.getId()==seekBar1.getId()){textView1.setText("當前seekbar1刻度"+position);}else {textView2.setText("當前seekbar2刻度"+position);}}@Overridepublic void onStartTrackingTouch(SeekBar seekBar) {// TODO Auto-generated method stubif (seekBar.getId()==seekBar1.getId()){textView1.setText("開始滑動seek1");}else {textView2.setText("開始滑動seek2");}}@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {// TODO Auto-generated method stubif (seekBar.getId()==seekBar1.getId()){textView1.setText("停止滑動seek1");}else {textView2.setText("停止滑動seek2");}}    }</span>

使用seekbar來控制螢幕的亮度

xml檔案

<span style="font-size:18px;"><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="fill_parent"        android:layout_height="wrap_content"        android:layout_alignParentTop="true"        android:layout_centerHorizontal="true"        android:layout_marginTop="24dp"        android:text="調節手機亮度" />    <SeekBar        android:max="100"        android:id="@+id/seekBar1"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/textView1"        android:layout_below="@+id/textView1"        android:layout_marginTop="117dp"        android:progress="50" /></RelativeLayout></span>

ＪＡＶＡ檔案

<span style="font-size:18px;">package com.example.seekbardemo;import android.app.Activity;import android.os.Bundle;import android.view.WindowManager;import android.widget.SeekBar;import android.widget.SeekBar.OnSeekBarChangeListener;public class MainActivity extends Activity implements OnSeekBarChangeListener {private SeekBar myseekBar;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);myseekBar=(SeekBar)this.findViewById(R.id.seekBar1);myseekBar.setOnSeekBarChangeListener(this);}@Overridepublic void onProgressChanged(SeekBar seekBar, int position, boolean flag) {// TODO Auto-generated method stub}//調節亮度的方法private void setScreenBrightness(float num) {WindowManager.LayoutParams layoutParams = getWindow().getAttributes();// 取得window屬性layoutParams.screenBrightness = num;// num已經除以100super.getWindow().setAttributes(layoutParams); // 0~1之間}@Overridepublic void onStartTrackingTouch(SeekBar arg0) {// TODO Auto-generated method stub}//在拖動結束是使用getProgress獲得當前的Progress值來設定亮度@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {// TODO Auto-generated method stubif (seekBar.getId()==myseekBar.getId()) {//將progress除以100並轉換為float類型setScreenBrightness((float)seekBar.getProgress()/100);}}}</span>

改變後



當然，使用SeekBar組件也可以對音量進行控制，大家可以查詢相關ＡＰＩ自行嘗試





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