android ImageView實現上面圓角下面直角(自定義view實現)
阿新 • • 發佈:2019-01-02
主要思想:
重寫imageview,在imageview上畫一個四個圓角的方框,並把畫布下一一個圓角半徑長度,這樣就能不顯示下面對的四個角
重寫ImageView:
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.widget.ImageView;
class RoundImageView extends ImageView {
public RoundImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public RoundImageView(Context context) {
super (context);
init();
}
private final RectF roundRect = new RectF();
private float rect_adius = 15;
private final Paint maskPaint = new Paint();
private final Paint zonePaint = new Paint();
private void init() {
maskPaint.setAntiAlias(true);
maskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
zonePaint.setAntiAlias(true);
zonePaint.setColor(Color.WHITE);
float density = getResources().getDisplayMetrics().density;
rect_adius = rect_adius * density;
}
public void setRectAdius(float adius) {
rect_adius = adius;
invalidate();
}
@Override
protected void onLayout(boolean changed, int left, int top, int right,
int bottom) {
super.onLayout(changed, left, top, right, bottom);
int w = getWidth();
int h = getHeight();
roundRect.set(0, 0, w, h + rect_adius);//畫布下移半徑長度
}
@Override
public void draw(Canvas canvas) {
canvas.saveLayer(roundRect, zonePaint, Canvas.ALL_SAVE_FLAG);
canvas.drawRoundRect(roundRect, rect_adius, rect_adius, zonePaint);
canvas.saveLayer(roundRect, maskPaint, Canvas.ALL_SAVE_FLAG);
super.draw(canvas);
canvas.restore();
}
}
注:該類可以直接在xml中呼叫,和imageView用法一樣,不過圓角半徑要動態在程式碼中設定,呼叫該物件的setRectAdius(adius)方法