Android 自定义textview实现跑马灯效果
直接上代码：
public class CustomTextView extends View { /** * 界面刷新时间(ms) */ public static final int INVALIDATE_TIME = 15; /** * 每次移动的像素点(px) */ public static final int INVALIDATE_STEP = 4; /** * 一次移动完成后等待的时间(ms) */ public static final int WAIT_TIME = 1500; /** * 滚动文字前后的间隔 */ private String space = " "; private String drawingText = ""; private TextPaint paint; public boolean exitFlag; private float textWidth; private String _mText; private int posX = 50; private float posY = 50; private int width; private RectF rf; private Handler mHandler = new Handler(); public CustomTextView(Context context) { this(context, null); } public CustomTextView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public CustomTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initView(); } private void initView() { paint = new TextPaint(); paint.setAntiAlias(true); paint.setColor(Color.WHITE); paint.setTextSize(30F); rf = new RectF(0, 0, 0, 0); } public void setText(String text) { this._mText = text; this.drawingText = _mText; layoutView(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(widthMeasureSpec, heightMeasureSpec); layoutView(); } private void layoutView() { width = getWidth(); rf.right = width; rf.bottom = getHeight(); textWidth = paint.measureText(_mText, 0, _mText.length()); posY = getTextDrawingBaseline(paint, rf); } @Override protected void onDraw(Canvas canvas) { if (getVisibility() != View.VISIBLE || TextUtils.isEmpty(drawingText)) { return; } canvas.save(); canvas.drawText(drawingText, 0, drawingText.length(), posX, posY, paint); canvas.restore(); } private Runnable moveRun = new Runnable() { @Override public void run() { if(width >= textWidth){ return; } drawingText = _mText + space + _mText; posX -= INVALIDATE_STEP; if(posX >= -1 * INVALIDATE_STEP / 2 && posX <= INVALIDATE_STEP / 2){ mHandler.postDelayed(this, WAIT_TIME); invalidate(); return; } if (posX < -1 * textWidth - paint.measureText(space, 0, space.length())) { posX = INVALIDATE_STEP; } invalidate(); if(!exitFlag){ mHandler.postDelayed(this, INVALIDATE_TIME); return; } posX = 0; } }; @Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); stopMove(); } @Override public void onWindowFocusChanged(boolean hasWindowFocus) { super.onWindowFocusChanged(hasWindowFocus); layoutView(); startMove(); } private void stopMove() { exitFlag = true; mHandler.removeCallbacksAndMessages(null); } public void startMove() { exitFlag = false; mHandler.post(moveRun); } /** * 获取绘制文字的baseline * * @param paint * @param targetRect * @return */ public static float getTextDrawingBaseline(Paint paint, RectF targetRect) { if (paint == null || targetRect == null) { return 0; } Paint.FontMetrics fontMetric = paint.getFontMetrics(); return targetRect.top + (targetRect.height() - fontMetric.bottom + fontMetric.top) / 2.0f - fontMetric.top; } } main.xml文件
<test.bwei.com.handler.CustomTextView android:id="@+id/mm" android:gravity="center" android:layout_width="wrap_content" android:layout_height="wrap_content" />
main方法：
public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); RelativeLayout rl = new RelativeLayout(MainActivity.this); setContentView(rl); CustomTextView view = new CustomTextView(MainActivity.this); view.setBackgroundColor(Color.CYAN); view.setText("不忘初心 方得始终 吃得苦中苦 方为人上人"); rl.addView(view, 300, 100); } }
