二、实现原理:
这个其实不难实现,通过一个定时器不断调用TextView
的setText
就行了,在setText
的时候播放打字的音效。
具体代码如下:
import java.util.Timer;import java.util.TimerTask;import android.content.Context;import android.media.MediaPlayer;import android.text.TextUtils;import android.util.AttributeSet;import android.widget.TextView;import com.uperone.typetextview.R;/** * 模拟打字机效果 ** */public class TypeTextView extends TextView { private Context mContext = null; private MediaPlayer mMediaPlayer = null; private String mShowTextString = null; private Timer mTypeTimer = null; private OnTypeViewListener mOnTypeViewListener = null; private static final int TYPE_TIME_DELAY = 80; private int mTypeTimeDelay = TYPE_TIME_DELAY; // 打字间隔 public TypeTextView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);initTypeTextView( context ); } public TypeTextView(Context context, AttributeSet attrs) {super(context, attrs);initTypeTextView( context ); } public TypeTextView(Context context) {super(context);initTypeTextView( context ); } public void setOnTypeViewListener( OnTypeViewListener onTypeViewListener ){mOnTypeViewListener = onTypeViewListener; } public void start( final String textString ){start( textString, TYPE_TIME_DELAY ); } public void start( final String textString, final int typeTimeDelay ){if( TextUtils.isEmpty( textString ) || typeTimeDelay < 0 ){ return;}post( new Runnable( ) { @Override public void run() {mShowTextString = textString;mTypeTimeDelay = typeTimeDelay;setText( "" );startTypeTimer( );if( null != mOnTypeViewListener ){ mOnTypeViewListener.onTypeStart( );} }}); } public void stop( ){stopTypeTimer( );stopAudio(); } private void initTypeTextView( Context context ){mContext = context; } private void startTypeTimer( ){stopTypeTimer( );mTypeTimer = new Timer( );mTypeTimer.schedule( new TypeTimerTask(), mTypeTimeDelay ); } private void stopTypeTimer( ){if( null != mTypeTimer ){ mTypeTimer.cancel( ); mTypeTimer = null;} } private void startAudioPlayer() {stopAudio();playAudio( R.raw.type_in ); } private void playAudio( int audioResId ){try{ stopAudio( ); mMediaPlayer = MediaPlayer.create( mContext, audioResId ); mMediaPlayer.start( );}catch( Exception e ){ e.printStackTrace();} } private void stopAudio( ){if( mMediaPlayer != null && mMediaPlayer.isPlaying( ) ){ mMediaPlayer.stop( ); mMediaPlayer.release( ); mMediaPlayer = null;} } class TypeTimerTask extends TimerTask{@Overridepublic void run() { post(new Runnable( ) {@Overridepublic void run() { if( getText( ).toString( ).length( ) < mShowTextString.length( ) ){setText( mShowTextString.substring(0, getText( ).toString( ).length( ) + 1 ) );startAudioPlayer();startTypeTimer( ); }else{stopTypeTimer( );if( null != mOnTypeViewListener ){ mOnTypeViewListener.onTypeOver( );} }} });} } public interface OnTypeViewListener{public void onTypeStart( );public void onTypeOver( ); }}三、使用说明:
<com.uperone.typetext.view.TypeTextViewandroid:id="@+id/typeTxtId"android:layout_width="fill_parent"android:layout_height="wrap_content"android:layout_centerVertical="true" />2、在代码中实例化:
mTypeTextView = ( TypeTextView )findViewById(R.id.typeTxtId); mTypeTextView.setOnTypeViewListener( new OnTypeViewListener( ) {@Overridepublic void onTypeStart() { print( "onTypeStart" );}@Overridepublic void onTypeOver() { print( "onTypeOver" );} });3、调用start方法:
mTypeTextView.start( TEST_DATA );四、总结