问题
I have a frame layout call view_snap_tabs.xml that have image and view like below
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="184dp"
xmlns:tools="http://schemas.android.com/tools"
tools:layout_gravity="bottom"
tools:background="@color/light_purple">
<ImageView
android:id="@+id/vst_bottom_image"
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_marginBottom="48dp"
android:layout_gravity="center|bottom"
android:src="@drawable/small_circle"/>
<View
android:id="@+id/vst_indicator"
android:layout_width="48dp"
android:layout_height="4dp"
android:layout_gravity="bottom|center"
android:layout_marginBottom="44dp"
android:background="@drawable/indicator_background"/>
</FrameLayout>
I have included this layout in my activity_main.xml like below
<include
layout="@layout/view_snap_tabs"
android:id="@+id/am_snap_tabs"
android:layout_alignParentBottom="true"
android:layout_height="wrap_content"
android:layout_width="match_parent"/>
I have created a method call SetUpViewPager and I'm trying to add that method in main activity like below
SnapTabView snapTabView = findViewById(R.id.am_snap_tabs);
snapTabView.setUpWithViewPager(viewPager);
But when I run the application It will crash from there and give a ClassCastExeception how can I fix this?
EDITED====================================================================
public class SnapTabView extends FrameLayout implements ViewPager.OnPageChangeListener {
private ImageView mCenterImage;
private ImageView mStartImage;
private ImageView mBottomImage;
private ImageView mEndImage;
private View mIndicator;
private ArgbEvaluator mArgbEvaluator;
private int mCenterColor;
private int mSideColor;
private int mEndViewsTranslationX;
private int mIndicatorTranslationX;
private int mCenterTransationY;
public SnapTabView(@NonNull Context context) {
this(context, null);
}
public SnapTabView(@NonNull Context context, @Nullable AttributeSet attrs) {
this(context, attrs, 0);
}
public SnapTabView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
LayoutInflater.from(getContext()).inflate(R.layout.view_snap_tabs, this, false);
mCenterImage = (ImageView) findViewById(R.id.vst_center_image);
mBottomImage = (ImageView) findViewById(R.id.vst_bottom_image);
mEndImage = (ImageView) findViewById(R.id.vst_end_image);
mStartImage = (ImageView) findViewById(R.id.vst_start_image);
mIndicator = (View) findViewById(R.id.vst_indicator);
mCenterColor = ContextCompat.getColor(getContext(), R.color.white);
mSideColor = ContextCompat.getColor(getContext(), R.color.dark_grey);
mArgbEvaluator = new ArgbEvaluator();
mIndicatorTranslationX = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 80, getResources().getDisplayMetrics());
mBottomImage.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
mEndViewsTranslationX = (int) ((mBottomImage.getX() - mStartImage.getX()) - mIndicatorTranslationX);
mBottomImage.getViewTreeObserver().removeOnGlobalLayoutListener(this);
mCenterTransationY = getHeight() - mBottomImage.getBottom();
}
});
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if(position == 0) {
setColor(1 - positionOffset);
moveViews(1 - positionOffset);
mIndicator.setTranslationX((positionOffset - 1) * mIndicatorTranslationX);
moveAndScaleCenter(1 - positionOffset);
} else if(position == 1) {
setColor(positionOffset);
moveViews(positionOffset);
mIndicator.setTranslationX(positionOffset * mIndicatorTranslationX);
moveAndScaleCenter(positionOffset);
}
}
public void setUpWithViewPager(final ViewPager viewPager) {
viewPager.addOnPageChangeListener(this);
mStartImage.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
if(viewPager.getCurrentItem() != 0)
viewPager.setCurrentItem(0);
}
});
mEndImage.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
if(viewPager.getCurrentItem() != 2)
viewPager.setCurrentItem(2);
}
});
}
@Override
public void onPageSelected(int position) {
}
@Override
public void onPageScrollStateChanged(int state) {
}
private void setColor(float fractionFromCenter) {
int color = (int) mArgbEvaluator.evaluate(fractionFromCenter, mCenterColor, mSideColor);
mCenterImage.setColorFilter(color);
mStartImage.setColorFilter(color);
mEndImage.setColorFilter(color);
}
private void moveViews(float fractionFromCenter) {
mStartImage.setTranslationX(fractionFromCenter * mEndViewsTranslationX);
mEndImage.setTranslationX(-fractionFromCenter * mEndViewsTranslationX);
mIndicator.setAlpha(fractionFromCenter);
mIndicator.setScaleX(fractionFromCenter);
}
private void moveAndScaleCenter(float fractionFromCenter) {
float scale = .7f + ((1 - fractionFromCenter) * .3f);
mCenterImage.setScaleX(scale);
mCenterImage.setScaleY(scale);
int translation = (int) (fractionFromCenter * mCenterTransationY);
mCenterImage.setTranslationY(translation);
mBottomImage.setTranslationY(translation);
mBottomImage.setAlpha(1 - fractionFromCenter);
}
}
view_snap_tabs.xml file like below
<?xml version="1.0" encoding="utf-8"?>
<com.example.crowderia.chat.view.SnapTabView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="184dp"
tools:layout_gravity="bottom"
tools:background="@color/light_purple"
android:id="@+id/snaps">
<ImageView
android:id="@+id/vst_center_image"
android:layout_width="88dp"
android:layout_height="88dp"
android:layout_gravity="center|bottom"
android:src="@drawable/large_circle"
android:layout_marginBottom="96dp"/>
<ImageView
android:id="@+id/vst_start_image"
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_marginBottom="56dp"
android:layout_marginStart="24dp"
android:layout_gravity="start|bottom"
android:src="@drawable/ic_chat_bubble_24dp"/>
<ImageView
android:id="@+id/vst_end_image"
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_marginBottom="56dp"
android:layout_marginEnd="24dp"
android:layout_gravity="end|bottom"
android:src="@drawable/ic_group_work_24dp"/>
<ImageView
android:id="@+id/vst_bottom_image"
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_marginBottom="48dp"
android:layout_gravity="center|bottom"
android:src="@drawable/small_circle"/>
<View
android:id="@+id/vst_indicator"
android:layout_width="48dp"
android:layout_height="4dp"
android:layout_gravity="bottom|center"
android:layout_marginBottom="44dp"
android:background="@drawable/indicator_background"/>
</com.example.crowderia.chat.view.SnapTabView>
回答1:
do this:
<?xml version="1.0" encoding="utf-8"?>
<com.example.crowderia.chat.view.SnapTabView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="184dp"
android:id="@+id/snaps"
xmlns:tools="http://schemas.android.com/tools">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="184dp"
tools:layout_gravity="bottom"
tools:background="@color/light_purple">
<ImageView
android:id="@+id/vst_bottom_image"
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_marginBottom="48dp"
android:layout_gravity="center|bottom"
android:src="@drawable/small_circle"/>
<View
android:id="@+id/vst_indicator"
android:layout_width="48dp"
android:layout_height="4dp"
android:layout_gravity="bottom|center"
android:layout_marginBottom="44dp"
android:background="@drawable/indicator_background"/>
</FrameLayout>
</com.example.crowderia.chat.view.SnapTabView>
in the activity do this:
View view=findViewById(R.id.am_snap_tabs);
SnapTabView snap=(SnapTabView)view.findViewById(R.id.snaps);
snap.setUpWithViewPager(viewPager);
//am_snap_tabs it is the id of the include in the question
回答2:
It's because you are trying to assign a view with FrameLayout to SnapTabView, modify your xml as below
view_snap_tabs.xml
<?xml version="1.0" encoding="utf-8"?>
<com.example.crowderia.chat.view.SnapTabView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="184dp"
xmlns:tools="http://schemas.android.com/tools">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="184dp"
tools:layout_gravity="bottom"
tools:background="@color/light_purple">
<ImageView
android:id="@+id/vst_bottom_image"
android:layout_width="32dp"
android:layout_height="32dp"
android:layout_marginBottom="48dp"
android:layout_gravity="center|bottom"
android:src="@drawable/small_circle"/>
<View
android:id="@+id/vst_indicator"
android:layout_width="48dp"
android:layout_height="4dp"
android:layout_gravity="bottom|center"
android:layout_marginBottom="44dp"
android:background="@drawable/indicator_background"/>
</FrameLayout>
</com.example.crowderia.chat.view.SnapTabView>
来源：https://stackoverflow.com/questions/47343123/android-widget-framelayout-cannot-be-cast-to-com-example-crowderia-chat-view-sna