Android开发：TextView真正可控、不需要焦点的水平滚动--这才是真正的跑马灯

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();

             }

         });

    }

}

Demo下载

巴特西

Android开发：TextView真正可控、不需要焦点的水平滚动--这才是真正的跑马灯

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