android开发常见bug及解决方案汇总

一、滑动冲突

1、ScrollView和ViewPager

public class CustomScrollView extends ScrollView {

private float xDistance, yDistance, xLast, yLast;

public CustomScrollView(Context context) {
super(context);
}

public CustomScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}

public CustomScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
xDistance = yDistance = 0f;
xLast = ev.getX();
yLast = ev.getY();
break;
case MotionEvent.ACTION_MOVE:
final float curX = ev.getX();
final float curY = ev.getY();

xDistance += Math.abs(curX - xLast);
yDistance += Math.abs(curY - yLast);
xLast = curX;
yLast = curY;

if (xDistance > yDistance) {
return false;
}
}

return super.onInterceptTouchEvent(ev);
}
}

2、两个HorizontalScrollView同步滑动

/**
* 监听滑动事件，解决两个HorizontalScrollView的同步滑动
*/
public class ObservableScrollView extends HorizontalScrollView {
private ScrollViewListener scrollViewListener = null;

public ObservableScrollView(Context context) {
super(context);
}

public ObservableScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}

public ObservableScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

public void setScrollViewListener(ScrollViewListener scrollViewListener) {
this.scrollViewListener = scrollViewListener;
}

@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (scrollViewListener != null) {
scrollViewListener.onScrollChanged(this, l, t, oldl, oldt);
}
}

public static interface ScrollViewListener {
void onScrollChanged(ObservableScrollView scrollView, int l, int t, int oldl, int oldt);
}
}

在Activity里的代码调用：

ObservableScrollView observableScrollView1;
ObservableScrollView observableScrollView2;
ObservableScrollView.ScrollViewListener scrollViewListener=new  ObservableScrollView.ScrollViewListener{
@Override
public void onScrollChanged(ObservableScrollView scrollView, int l, int t, int oldl, int oldt) {
if (scrollView == observableScrollView1) {
observableScrollView2.scrollTo(l, t);
} else if (scrollView == observableScrollView2) {
observableScrollView1.scrollTo(l, t);
}
}
};
observableScrollView1.setScrollViewListener(scrollViewListener);
observableScrollView2.setScrollViewListener(scrollViewListener);

二、ScrollView、ListView、GridView 嵌套显示不完整
1、GridView嵌套显示不完整

public class CustomGridView extends GridView {
public CustomGridView(Context context) {
super(context);
}

public CustomGridView(Context context, AttributeSet attrs) {
super(context, attrs);
}

public CustomGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}

/**
* 设置不滚动
*/
@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}

}

2、ScrollView嵌套GridView ，ScrollView定位不准，UI抖动

gridView .setFocusable(false);
new Handler().post(new Runnable() {
@Override
public void run() {
scrollView.smoothScrollTo(0, 1);
}
});

三、网络图片自适应（通常应用于图片宽度全屏，高度等比例自适配）

XML布局文件ImageView属性设置：

<ImageView
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="centerCrop"
android:src="@drawable/default"
/>

1、单张图片显示、ListView图片列表显示

java代码：

ImageView imageView = (ImageView) findViewById(R.id.image);
ViewGroup.LayoutParams lp = imageView.getLayoutParams();
lp.width = screenWidth;//屏幕宽度
lp.height = lp.width * 258 / 640;//图片宽高
imageView.setLayoutParams(lp);
imageView.setImageDrawable(getResources().getDrawable(R.drawable.default));//默认占位图

2、ViewPager图片滑动显示

XML布局文件ViewPager属性设置：

<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>

java代码：

ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
viewPager.setAdapter(PagerAdapter);
viewPager.setOnPageChangeListener(this);
ViewGroup.LayoutParams lp = viewPager.getLayoutParams();
lp.width = screenWidth;//<span style="font-family: Arial, Helvetica, sans-serif;">屏幕宽度</span>
lp.height = lp.width * 258 / 640;<span style="font-family: Arial, Helvetica, sans-serif;">//图片宽高</span>
viewPager.setLayoutParams(lp);

在PagerAdapter的instantiateItem()方法中：

ImageView imageView = (ImageView) findViewById(R.id.image);
ViewGroup.LayoutParams lp = imageView.getLayoutParams();
lp.width = screenWidth;//屏幕宽度
lp.height = lp.width * 258 / 640;//图片宽高
imageView.setLayoutParams(lp);
imageView.setImageDrawable(getResources().getDrawable(R.drawable.default));//默认占位图

四、