网上的TextView做跑马灯，大多都是要用到焦点，而且字数要超出滚动区域宽度才能实现滚动，使用起来十分不方便。
这里实现一种真正可控的滚动
(1)不需要焦点
(2)任意字数
(3)滚动从滚动区域右边出来，在左边消失，再从右边出来。
上代码
1、布局文件
<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"
tools:context="${relativePackage}.${activityClass}" > <Button
android:id="@+id/btn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="改变滚动内容1"/>
<Button
android:id="@+id/btn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/btn1"
android:text="改变滚动内容2"/>
<Button
android:id="@+id/btn3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/btn2"
android:text="退出程序"/>
<com.using.margindemo.MarqueeTextView
android:id="@+id/tvScroll"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="40dp" >
</com.using.margindemo.MarqueeTextView>
</RelativeLayout>
2、滚动控件
package com.using.margindemo; import android.content.Context;
import android.graphics.Canvas;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.widget.TextView; public class MarqueeTextView extends TextView { /** 是否停止滚动 */
private boolean mStopMarquee;
private String mText;//文本内容
private float mCoordinateX = 1280;//当前滚动位置
private float mTextWidth;//文本宽度
private int mScrollWidth = 1280;//滚动区域宽度
private int speed = 1;//滚动速度
public float getCurrentPosition() {
return mCoordinateX;
} public void setCurrentPosition(float mCoordinateX) {
this.mCoordinateX = mCoordinateX;
} public int getScrollWidth() {
return mScrollWidth;
} public void setScrollWidth(int mScrollWidth) {
this.mScrollWidth = mScrollWidth;
} public int getSpeed() {
return speed;
} public void setSpeed(int speed) {
this.speed = speed;
} public MarqueeTextView(Context context, AttributeSet attrs) {
super(context, attrs);
} public void setText(String text) {
this.mText = text;
mTextWidth = getPaint().measureText(mText);
//mTextWidth = 1280;
if (mHandler.hasMessages(0))
mHandler.removeMessages(0);
mHandler.sendEmptyMessageDelayed(0, 10);
} @Override
protected void onAttachedToWindow() {
mStopMarquee = false;
if (!isEmpty(mText))
mHandler.sendEmptyMessageDelayed(0, 2000);
super.onAttachedToWindow();
} public static boolean isEmpty(String str) {
return str == null || str.length() == 0;
} @Override
protected void onDetachedFromWindow() {
mStopMarquee = true;
if (mHandler.hasMessages(0))
mHandler.removeMessages(0);
super.onDetachedFromWindow();
} @Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (!isEmpty(mText))
canvas.drawText(mText, mCoordinateX, 150, getPaint());
} private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
if (mCoordinateX < (-mTextWidth)) {//文字滚动完了，从滚动区域的右边出来
mCoordinateX = mScrollWidth;
invalidate();
if (!mStopMarquee) {
sendEmptyMessageDelayed(0, 500);
}
} else {
mCoordinateX -= speed;
invalidate();
if (!mStopMarquee) {
sendEmptyMessageDelayed(0, 30);
}
} break;
}
super.handleMessage(msg);
}
}; }
3、
package com.using.margindemo; import android.app.ActionBar;
import android.app.Activity;
import android.content.res.Configuration;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.MarginLayoutParams;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RelativeLayout; public class MainActivity extends Activity {
private ImageView image;
private MarqueeTextView marqueeTextView;
private Button button1;
private Button button2;
private Button button3;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);//隐藏标题栏
setContentView(R.layout.activity_main); marqueeTextView = (MarqueeTextView)findViewById(R.id.tvScroll); MarginLayoutParams margin1 = new MarginLayoutParams(
marqueeTextView.getLayoutParams());
margin1.setMargins(100, 200, 0, 0);//设置滚动区域位置：在左边距400像素，顶边距10像素的位置
RelativeLayout.LayoutParams layoutParams1 = new RelativeLayout.LayoutParams(margin1);
layoutParams1.height = 240;//设滚动区域高度
layoutParams1.width = 1000; //设置滚动区域宽度
marqueeTextView.setLayoutParams(layoutParams1);
marqueeTextView.setScrollWidth(1000);
marqueeTextView.setCurrentPosition(100 + 1000);//设置滚动信息从滚动区域的右边出来
marqueeTextView.setSpeed(2);
marqueeTextView.setText("这才是真正的跑马灯效果！");
button1 = (Button)findViewById(R.id.btn1);
button2 = (Button)findViewById(R.id.btn2);
button3 = (Button)findViewById(R.id.btn3);
button1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
marqueeTextView.setText("这才是真正的跑马灯效果！");
}
}); button2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
marqueeTextView.setText("温馨提示：挂号或缴费后，请到休息区等候，我们会尽快为您服务，请留意屏幕叫号信息，谢谢！"); }
});
button3.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});
}
}