android文字描边功能的实现

public class StrokeTextView extends TextView
{
 private TextView outlineTextView = null;
 
  public StrokeTextView(Context context)
  {
    super(context);
    
    outlineTextView = new TextView(context);
    init();
  }
 
  public StrokeTextView(Context context, AttributeSet attrs) 
  {
    super(context, attrs);
    
    outlineTextView = new TextView(context, attrs);
    init();
  }
 
  public StrokeTextView(Context context, AttributeSet attrs, int defStyle) 
  {
    super(context, attrs, defStyle);
    
    outlineTextView = new TextView(context, attrs, defStyle);
    init();
  }
 
  public void init()
  {
    TextPaint paint = outlineTextView.getPaint();
    paint.setStrokeWidth(3);// 描边宽度
    paint.setStyle(Style.STROKE);
    outlineTextView.setTextColor(Color.parseColor("#45c01a"));// 描边颜色
    outlineTextView.setGravity(getGravity());
  }
 
  @Override
  public void setLayoutParams (ViewGroup.LayoutParams params)
  {
    super.setLayoutParams(params);
    outlineTextView.setLayoutParams(params);
  }
 
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) 
  {
   super.onMeasure(widthMeasureSpec, heightMeasureSpec);
   
    // 设置轮廓文字
   CharSequence outlineText = outlineTextView.getText();
    if (outlineText == null || !outlineText.equals(this.getText()))
    {
     outlineTextView.setText(getText());
      postInvalidate();
    }
    outlineTextView.measure(widthMeasureSpec, heightMeasureSpec);
  }
 
  @Override
  protected void onLayout (boolean changed, int left, int top, int right, int bottom)
  {
    super.onLayout(changed, left, top, right, bottom);
    outlineTextView.layout(left, top, right, bottom);
  }
 
  @Override
  protected void onDraw(Canvas canvas)
  {
   outlineTextView.draw(canvas);
    super.onDraw(canvas);
  }
}

<com.my.teststroketextview.StrokeTextView
    android:id="@+id/test_stroketextview"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    android:textSize="25sp"
    android:textColor="@color/dark_gray"
    android:text="@string/hello_world" />

private StrokeTextView test_stroketextview = null;
 
@Override
protected void onCreate(Bundle savedInstanceState)
{
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 
 test_stroketextview = (StrokeTextView)findViewById(R.id.test_stroketextview);
 test_stroketextview.setText("Hello world!");
}