Android WindowManager悬浮显示歌词

package com.yfz.view; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.LinearGradient; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.Shader; import android.graphics.Typeface; import android.graphics.Shader.TileMode; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.view.WindowManager; import android.widget.TextView; import android.widget.Toast; public class MyTextView extends TextView { private final String TAG = MyTextView.class.getSimpleName(); public static int TOOL_BAR_HIGH = 0; public static WindowManager.LayoutParams params = new WindowManager.LayoutParams(); private float startX; private float startY; private float x; private float y; private String text; WindowManager wm = (WindowManager)getContext().getApplicationContext().getSystemService(getContext().WINDOW_SERVICE); public MyTextView(Context context) { super(context); text = "世上只有妈妈好,有妈的孩子像块宝"; this.setBackgroundColor(Color.argb(90, 150, 150, 150)); // 下面这句话在此并不是控制歌词大小，仅仅是为了控制背景大小，如果不设置的话，Paint字体大时会被遮挡 this.setTextSize(20f); } @Override public boolean onTouchEvent(MotionEvent event) { //触摸点相对于屏幕左上角坐标 x = event.getRawX(); y = event.getRawY() - TOOL_BAR_HIGH; Log.d(TAG, "------X: "+ x +"------Y:" + y); switch(event.getAction()) { case MotionEvent.ACTION_DOWN: startX = event.getX(); startY = event.getY(); break; case MotionEvent.ACTION_MOVE: updatePosition(); break; case MotionEvent.ACTION_UP: updatePosition(); startX = startY = 0; break; } return true; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); float1 += 0.001f; float2 += 0.001f; if(float2 > 1.0){ float1 = 0.0f; float2 = 0.01f; } this.setText(""); float len = this.getTextSize() * text.length(); Shader shader = new LinearGradient(0, 0, len, 0, new int[] { Color.YELLOW, Color.RED }, new float[]{float1, float2}, TileMode.CLAMP); Paint p = new Paint(); p.setShader(shader); // 下面这句才控制歌词大小 p.setTextSize(20f); p.setTypeface(Typeface.DEFAULT_BOLD); //此处x,y坐标也要注意，尤其是y坐标，要与字体大小协调 canvas.drawText(text, 0, 20, p); } private float float1 = 0.0f; private float float2 = 0.01f; //更新浮动窗口位置参数 private void updatePosition(){ // View的当前位置 params.x = (int)( x - startX); params.y = (int) (y - startY); wm.updateViewLayout(this, params); } }