public class MarqueeTextView extends TextView {
/** 是否停止滚动 */
private boolean mStopMarquee;
private String mText;
private float mCoordinateX;
private float mTextWidth;
public MarqueeTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setText(String text) {
this.mText = text;
mTextWidth = getPaint().measureText(mText);
if (mHandler.hasMessages(0))
mHandler.removeMessages(0);
mHandler.sendEmptyMessageDelayed(0, 2000);
}
@Override
protected void onAttachedToWindow() {
mStopMarquee = false;
if (!StringUtils.isEmpty(mText))
mHandler.sendEmptyMessageDelayed(0, 2000);
super.onAttachedToWindow();
}
@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 (!StringUtils.isEmpty(mText))
canvas.drawText(mText, mCoordinateX, 15, getPaint());
}
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
if (Math.abs(mCoordinateX) > (mTextWidth + 100)) {
mCoordinateX = 0;
invalidate();
if (!mStopMarquee) {
sendEmptyMessageDelayed(0, 2000);
}
} else {
mCoordinateX -= 1;
invalidate();
if (!mStopMarquee) {
sendEmptyMessageDelayed(0, 30);
}
}
break;
}
super.handleMessage(msg);
}
};
}
/** 是否停止滚动 */
private boolean mStopMarquee;
private String mText;
private float mCoordinateX;
private float mTextWidth;
public MarqueeTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setText(String text) {
this.mText = text;
mTextWidth = getPaint().measureText(mText);
if (mHandler.hasMessages(0))
mHandler.removeMessages(0);
mHandler.sendEmptyMessageDelayed(0, 2000);
}
@Override
protected void onAttachedToWindow() {
mStopMarquee = false;
if (!StringUtils.isEmpty(mText))
mHandler.sendEmptyMessageDelayed(0, 2000);
super.onAttachedToWindow();
}
@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 (!StringUtils.isEmpty(mText))
canvas.drawText(mText, mCoordinateX, 15, getPaint());
}
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0:
if (Math.abs(mCoordinateX) > (mTextWidth + 100)) {
mCoordinateX = 0;
invalidate();
if (!mStopMarquee) {
sendEmptyMessageDelayed(0, 2000);
}
} else {
mCoordinateX -= 1;
invalidate();
if (!mStopMarquee) {
sendEmptyMessageDelayed(0, 30);
}
}
break;
}
super.handleMessage(msg);
}
};
}
代码说明:
1、2000表示延迟2秒开始跑马灯效果
2、mTextWidth + 100 表示跑出屏幕100像素再重新开始跑
3、每30毫秒移动1像素
4、原理很简单,就是定时刷,用法很简单,直接setText就行,和用系统的一样,但是不能通过设置xml的值来直接跑,这个可以自己修改。
5、注意onDraw时判定一下text是否为空,这里StringUtils.isEmpty替换成自己的判定方法即可。
本文转自博客园农民伯伯的博客,原文链接:【Android】不依赖焦点和选中的TextView跑马灯【2】,如需转载请自行联系原博主。