自定义布局,使Viewpager显示上一页的一部分和下一页的一部分
Xml中的使用:(使用pagerContainer嵌套viewpager实现)
<com.example.testsurrondviewpager.PagerContainer
android:id="@+id/pager_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#CCC">
<com.example.testsurrondviewpager.MyRatioViewPager
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal" />
com.example.testsurrondviewpager.PagerContainer>
PagerContainer:
package com.example.testsurrondviewpager;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import android.content.Context;
import android.graphics.Paint;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.EdgeEffectCompat;
import android.util.AttributeSet;
import android.widget.FrameLayout;
public class PagerContainer extends FrameLayout implements ViewPager.OnPageChangeListener {
private ViewPager mPager;
boolean mNeedsRedraw = false;
private EdgeEffectCompat leftEdge;
private EdgeEffectCompat rightEdge;
public PagerContainer(Context context) {
super(context);
init();
}
public PagerContainer(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public PagerContainer(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
setClipChildren(false);
try {
Method setLayerTypeMethod = this.getClass().getMethod("setLayerType", new Class[] {int.class, Paint.class});
setLayerTypeMethod.invoke(this, new Object[] {LAYER_TYPE_SOFTWARE, null});
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
@Override
protected void onFinishInflate() {
try {
mPager = (ViewPager) getChildAt(0);
mPager.setOnPageChangeListener(this);
Field leftEdgeField = mPager.getClass().getSuperclass().getDeclaredField("mLeftEdge");
Field rightEdgeField = mPager.getClass().getSuperclass().getDeclaredField("mRightEdge");
if (leftEdgeField != null && rightEdgeField != null) {
leftEdgeField.setAccessible(true);
rightEdgeField.setAccessible(true);
leftEdge = (EdgeEffectCompat) leftEdgeField.get(mPager);
rightEdge = (EdgeEffectCompat) rightEdgeField.get(mPager);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public ViewPager getViewPager() {
return mPager;
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (mNeedsRedraw) invalidate();
if (leftEdge != null && rightEdge != null) {
leftEdge.finish();
rightEdge.finish();
leftEdge.setSize(0, 0);
rightEdge.setSize(0, 0);
}
}
@Override
public void onPageSelected(int position) { }
@Override
public void onPageScrollStateChanged(int state) {
mNeedsRedraw = (state != ViewPager.SCROLL_STATE_IDLE);
}
}
MyRatioViewpager:
package com.example.testsurrondviewpager;
import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
public class MyRatioViewPager extends ViewPager{
public MyRatioViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyRatioViewPager(Context context) {
super(context);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int size = (int) (MeasureSpec.getSize(widthMeasureSpec)/1.5);//这里可以设置viewpager两侧显示的大小
int mode = MeasureSpec.getMode(widthMeasureSpec);
widthMeasureSpec = MeasureSpec.makeMeasureSpec(size, mode);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}