android自定义刷新
时间: 2023-11-28 10:51:11 浏览: 31
Android自定义刷新可以通过继承View或ViewGroup来实现。以下是一个自定义刷新View的例子:
```java
public class CustomRefreshView extends View {
private Paint mPaint;
private RectF mRect;
private float mStartAngle;
private float mSweepAngle;
private boolean mIsRefreshing;
public CustomRefreshView(Context context) {
super(context);
init();
}
public CustomRefreshView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public CustomRefreshView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(8);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setColor(Color.BLUE);
mRect = new RectF();
mStartAngle = 0;
mSweepAngle = 0;
mIsRefreshing = false;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
setMeasuredDimension(width, height);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float centerX = getWidth() / 2;
float centerY = getHeight() / 2;
float radius = Math.min(centerX, centerY) - mPaint.getStrokeWidth() / 2;
mRect.set(centerX - radius, centerY - radius, centerX + radius, centerY + radius);
canvas.drawArc(mRect, mStartAngle, mSweepAngle, false, mPaint);
if (mIsRefreshing) {
mStartAngle += 10;
if (mStartAngle >= 360) {
mStartAngle -= 360;
}
invalidate();
}
}
public void startRefresh() {
mIsRefreshing = true;
mSweepAngle = 300;
invalidate();
}
public void stopRefresh() {
mIsRefreshing = false;
mSweepAngle = 0;
invalidate();
}
}
```
在这个例子中,我们继承了View类,并实现了自定义的onDraw()方法来绘制一个圆弧。我们还提供了两个公共方法startRefresh()和stopRefresh()来启动和停止刷新。在startRefresh()方法中,我们设置了mIsRefreshing标志为true,并设置了mSweepAngle的值为300度,这将使圆弧从0度开始绘制到300度。然后我们调用invalidate()方法来触发View的重绘。在onDraw()方法中,我们使用mStartAngle来控制圆弧的起始角度,并使用invalidate()方法来持续重绘,直到mIsRefreshing标志被设置为false。
我们可以像使用其他View一样,在布局文件中使用CustomRefreshView:
```xml
<com.example.CustomRefreshView
android:id="@+id/refreshView"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
```
然后在代码中使用startRefresh()和stopRefresh()方法来启动和停止刷新:
```java
CustomRefreshView refreshView = findViewById(R.id.refreshView);
refreshView.startRefresh();
// do some refreshing work
refreshView.stopRefresh();
```
这样,我们就可以通过自定义View来实现Android的刷新功能了。