android 跑马灯效果的另一种实现方法

来源：互联网发布：果壳app没数据编辑：程序博客网时间：2024/04/28 18:08

传统的实现跑马灯效果,要设置textview一些属性,还要重写textview的onFouce()方法,但是传统的跑马灯效果的速度不好控制,今天就不使用传统的方式实现,

布局文件：

<?xml version="1.0" encoding="utf-8"?><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="com.example.marqueetext.MainActivity">    <com.example.marqueetext.MarqueeText        android:layout_width="match_parent"        android:layout_height="40px"        android:background="#ff00ff"        android:layout_marginTop="100px"        /></RelativeLayout>

跑马灯自定义view

package com.example.marqueetext;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Handler;import android.os.Message;import android.util.AttributeSet;import android.util.Log;import android.view.View;import android.view.WindowManager;/** * Created by Adminis on 2016/8/26. */public class MarqueeText extends View {    private static final String TAG ="MarqueeText" ;    private int x = 0;//    private int screenWidth;    private int textWidth;    private boolean isMeasure;    private Paint mPaint;    private String str = "晚上6点,银海国际酒店的三楼,600多平方的伊甸园里,布置简约而又充满的年轻点气息";    private Handler mHandler = new Handler(){        @Override        public void handleMessage(Message msg) {            super.handleMessage(msg);            if(msg.what==1){                x-=5;                if(Math.abs(x)>=textWidth){                    x=screenWidth;                }                invalidate();                mHandler.sendEmptyMessageDelayed(1,50);            }        }    };    public MarqueeText(Context context) {        this(context,null);    }    public MarqueeText(Context context, AttributeSet attrs) {        this(context, attrs,0);    }    public MarqueeText(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        mPaint = new Paint();        mPaint.setAntiAlias(true);        mPaint.setColor(Color.WHITE);        mPaint.setTextSize(20);        WindowManager wm = ((MainActivity)context).getWindowManager();        screenWidth = wm.getDefaultDisplay().getWidth();    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        if(!isMeasure){            textWidth = (int) mPaint.measureText(str);            isMeasure = true;        }        canvas.drawText(str,x,25,mPaint);    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        setMeasuredDimension(screenWidth,dip2px(getContext(),40));    }    @Override    public void onWindowFocusChanged(boolean hasWindowFocus) {        super.onWindowFocusChanged(hasWindowFocus);        if(hasWindowFocus){            mHandler.sendEmptyMessage(1);        }else{            mHandler.removeCallbacks(null);        }    }    public static int dip2px(Context context, float dpValue) {        final float scale = context.getResources().getDisplayMetrics().density;        return (int) (dpValue * scale + 0.5f);    }    /**     * 根据手机的分辨率从 px(像素) 的单位 转成为 dp     */    public static int px2dip(Context context, float pxValue) {        final float scale = context.getResources().getDisplayMetrics().density;        return (int) (pxValue / scale + 0.5f);    }}

效果图：

这个在模拟器上看起来有点卡,但是我在真机上是没有这个问题的!

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