android 可以控制速度的跑马灯

1.自定义textview

public class ScrollTextView extends TextView {    // scrolling feature    private Scroller mSlr;    // milliseconds for a round of scrolling    private int mRndDuration = 100000;    // the X offset when paused    private int mXPaused = 0;    // whether it's being paused    private boolean mPaused = true;    /*    * constructor    */    public ScrollTextView(Context context) {        this(context, null);        // customize the TextView        setSingleLine();        setEllipsize(null);        setVisibility(INVISIBLE);    }    /*    * constructor    */    public ScrollTextView(Context context, AttributeSet attrs) {        this(context, attrs, android.R.attr.textViewStyle);        // customize the TextView        setSingleLine();        setEllipsize(null);        setVisibility(INVISIBLE);    }    /*    * constructor    */    public ScrollTextView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        // customize the TextView        setSingleLine();        setEllipsize(null);        setVisibility(INVISIBLE);    }    /**     * begin to scroll the text from the original position     */    public void startScroll() {        // begin from the very right side        mXPaused = -1 * getWidth();        // assume it's paused        mPaused = true;        resumeScroll();    }    /**     * resume the scroll from the pausing point     */    public void resumeScroll() {        if (!mPaused)            return;        // Do not know why it would not scroll sometimes        // if setHorizontallyScrolling is called in constructor.        setHorizontallyScrolling(true);        // use LinearInterpolator for steady scrolling        mSlr = new Scroller(this.getContext(), new LinearInterpolator());        setScroller(mSlr);        int scrollingLen = calculateScrollingLen();        int distance = scrollingLen - (getWidth() + mXPaused);        int duration = (new Double(mRndDuration * distance * 1.00000                / scrollingLen)).intValue();        setVisibility(VISIBLE);        mSlr.startScroll(mXPaused, 0, distance, 0, duration);        invalidate();        mPaused = false;    }    /**     * calculate the scrolling length of the text in pixel     *     * @return the scrolling length in pixels     */    private int calculateScrollingLen() {        TextPaint tp = getPaint();        Rect rect = new Rect();        String strTxt = getText().toString();        tp.getTextBounds(strTxt, 0, strTxt.length(), rect);        int scrollingLen = rect.width() + getWidth();        rect = null;        return scrollingLen;    }    /**     * pause scrolling the text     */    public void pauseScroll() {        if (null == mSlr)            return;        if (mPaused)            return;        mPaused = true;        // abortAnimation sets the current X to be the final X,        // and sets isFinished to be true        // so current position shall be saved        mXPaused = mSlr.getCurrX();        mSlr.abortAnimation();    }    @Override     /*     * override the computeScroll to restart scrolling when finished so as that     * the text is scrolled forever     */    public void computeScroll() {        super.computeScroll();        if (null == mSlr) return;        if (mSlr.isFinished() && (!mPaused)) {            this.startScroll();        }    }    public int getRndDuration() {        return mRndDuration;    }    public void setRndDuration(int duration) {        this.mRndDuration = duration;    }    public boolean isPaused() {        return mPaused;    }}

2.布局文件

activity_main11

xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >            android:id="@+id/start"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="start"        android:text="走起" />            android:id="@+id/stop"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="stop"        android:text="停止" />            android:id="@+id/startfor0"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="startFor0"        android:text="从头开始" />            android:id="@+id/test"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:background="#339320"        android:singleLine="true"        android:textColor="#000000"        android:textSize="20dp" >

3.mainActivity

public class MainActivity11 extends Activity implements View.OnClickListener {    private ScrollTextView test;    private Button start,stop,startfor0;    private List data;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main11);        test = (ScrollTextView) this.findViewById(R.id.test);        start = (Button) findViewById(R.id.start);        stop = (Button) findViewById(R.id.stop);        startfor0 = (Button) findViewById(R.id.startfor0);        start.setOnClickListener(this);        stop.setOnClickListener(this);        startfor0.setOnClickListener(this);        data = new ArrayList<>();        data.add("跑马灯1");        data.add("跑马灯2");        data.add("跑马灯3");        setAlwaysMarqueeTextViewData();    }    /**     * 设置最新咨询三条数据     */    private void setAlwaysMarqueeTextViewData(){        if(data!=null){//从集合里获取数据来显示在跑马灯上            test.setText(data.get(0)+";    "+data.get(1)+";    "+data.get(2));            test.startScroll();        }    }    @Override    public void onClick(View view) {        switch (view.getId()){            case R.id.start:                //开始                test.startScroll();                break;            case R.id.stop:                //停止                test.pauseScroll();                break;            case R.id.startfor0:                //从头开始                test.resumeScroll();                break;        }    }}

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