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public class ParallaxViewPager extends ViewPager {
private List fragments;
public ParallaxViewPager(Context context) {
this(context, null);
}
public ParallaxViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void attach(FragmentManager fm, int[] layoutIdRes) {
fragments = new ArrayList<>();
for (int i = 0; i < layoutIdRes.length; i++) {
ParallaxFragment fragment = new ParallaxFragment();
Bundle bundle = new Bundle();
bundle.putInt(fragment.LAYOUT_ID_KEY, layoutIdRes[i]);
if(i==layoutIdRes.length-1){
bundle.putBoolean("isLastFragment", true);
}else{
bundle.putBoolean("isLastFragment", false);
}
fragment.setArguments(bundle);
fragments.add(fragment);
}
ParallaxViewAdapter adapter = new ParallaxViewAdapter(fm);
setAdapter(adapter);
//监听滑动事件
addOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//出厂fragment
ParallaxFragment outFragment = fragments.get(position);
List parallaxViews = outFragment.getParallaxViews();
for (View parallaxView : parallaxViews) {
ParallaxTag tag = (ParallaxTag) parallaxView.getTag(R.id.parallax_tag);
parallaxView.setTranslationX((-positionOffsetPixels)*tag.translationXOut);
parallaxView.setTranslationY((-positionOffsetPixels)*tag.translationYOut);
}
try {
//进场fragment
ParallaxFragment inFragment = fragments.get(position+1);
parallaxViews = inFragment.getParallaxViews();
for (View parallaxView : parallaxViews) {
ParallaxTag tag = (ParallaxTag) parallaxView.getTag(R.id.parallax_tag);
parallaxView.setTranslationX((getMeasuredWidth()-positionOffsetPixels)*tag.translationXIn);
parallaxView.setTranslationY((getMeasuredWidth()-positionOffsetPixels)*tag.translationYIn);
}
}catch (Exception e){
}
}
@Override
public void onPageSelected(int position) {
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
class ParallaxViewAdapter extends FragmentPagerAdapter {
public ParallaxViewAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return (Fragment) fragments.get(position);
}
@Override
public int getCount() {
return fragments.size();
}
}
}
public class ParallaxFragment extends Fragment implements LayoutInflaterFactory {
public static final String LAYOUT_ID_KEY = "LAYOUT_ID_KEY";
private CompatViewInflater mCompatViewInflater;
private List mParallaxViews = new ArrayList<>();
private int[] attrsB = new int[]{R.attr.translationXIn, R.attr.translationXOut, R.attr.translationYIn, R.attr.translationYOut,};
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
//获取布局资源id
int anInt = getArguments().getInt(LAYOUT_ID_KEY);
// 2.2.2 把所有需要移动的属性解析出来，内涵端子插件式换肤
// View创建的时候 我们去解析属性 这里传 inflater 有没有问题？ 单例设计模式 代表着所有的View的创建都会是该 Fragment 去创建的
inflater = inflater.cloneInContext(getActivity());
LayoutInflaterCompat.setFactory(inflater, this);
return inflater.inflate(anInt, container, false);
}
@Override
public View onCreateView(View parent, String name, Context context, AttributeSet attrs) {
View view = createView(parent, name, context, attrs);
if (view != null) {
//进行属性解析
analysisAttrs(view, context, attrs);
}
//判断是否是最后一个fragment 是的话点击按钮进入程序主页
boolean isLastFragment = getArguments().getBoolean("isLastFragment", false);
if (isLastFragment) {
TextView goMain = (TextView) view.findViewById(R.id.go_main);
if (goMain != null) {
goMain.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(getActivity(), SecondActivity.class));
getActivity().finish();
}
});
}
}
return view;
}
private void analysisAttrs(View view, Context context, AttributeSet attrs) {
TypedArray array = context.obtainStyledAttributes(attrs, attrsB);
if (array != null && array.getIndexCount() != 0) {
int indexCount = array.getIndexCount();
ParallaxTag tag = new ParallaxTag();
//进行 遍历循环
for (int i = 0; i < indexCount; i++) {
int attr = array.getIndex(i);
switch (attr) {
case 0:
tag.translationXIn = array.getFloat(attr, 0f);
break;
case 1:
tag.translationXOut = array.getFloat(attr, 0f);
break;
case 2:
tag.translationYIn = array.getFloat(attr, 0f);
break;
case 3:
tag.translationYOut = array.getFloat(attr, 0f);
break;
}
}
// 自定义属性怎么存? 还要一一绑定 在View上面设置一个tag
view.setTag(R.id.parallax_tag, tag);
Log.e("TAG", tag.toString());
mParallaxViews.add(view);
}
array.recycle();
}
public View createView(View parent, final String name, @NonNull Context context,
@NonNull AttributeSet attrs) {
final boolean isPre21 = Build.VERSION.SDK_INT < 21;
if (mCompatViewInflater == null) {
mCompatViewInflater = new CompatViewInflater();
}
// We only want the View to inherit it's context if we're running pre-v21
final boolean inheritContext = isPre21 && true
&& shouldInheritContext((ViewParent) parent);
return mCompatViewInflater.createView(parent, name, context, attrs, inheritContext,
isPre21, /* Only read android:theme pre-L (L+ handles this anyway) */
true /* Read read app:theme as a fallback at all times for legacy reasons */
);
}
private boolean shouldInheritContext(ViewParent parent) {
if (parent == null) {
// The initial parent is null so just return false
return false;
}
while (true) {
if (parent == null) {
// Bingo. We've hit a view which has a null parent before being terminated from
// the loop. This is (most probably) because it's the root view in an inflation
// call, therefore we should inherit. This works as the inflated layout is only
// added to the hierarchy at the end of the inflate() call.
return true;
} else if (!(parent instanceof View)
|| ViewCompat.isAttachedToWindow((View) parent)) {
// We have either hit the window's decor view, a parent which isn't a View
// (i.e. ViewRootImpl), or an attached view, so we know that the original parent
// is currently added to the view hierarchy. This means that it has not be
// inflated in the current inflate() call and we should not inherit the context.
return false;
}
parent = parent.getParent();
}
}
public List getParallaxViews() {
return mParallaxViews;
}
}
public class CompatViewInflater {
private static final Class[] sConstructorSignature = new Class[]{
Context.class, AttributeSet.class};
private static final int[] sOnClickAttrs = new int[]{android.R.attr.onClick};
private static final String LOG_TAG = "AppCompatViewInflater";
private static final Map> sConstructorMap
= new ArrayMap<>();
private final Object[] mConstructorArgs = new Object[2];
public final View createView(View parent, final String name, @NonNull Context context,
@NonNull AttributeSet attrs, boolean inheritContext,
boolean readAndroidTheme, boolean readAppTheme) {
final Context originalContext = context;
// We can emulate Lollipop's android:theme attribute propagating down the view hierarchy
// by using the parent's context
if (inheritContext && parent != null) {
context = parent.getContext();
}
if (readAndroidTheme || readAppTheme) {
// We then apply the theme on the context, if specified
context = themifyContext(context, attrs, readAndroidTheme, readAppTheme);
}
View view = null;
// We need to 'inject' our tint aware Views in place of the standard framework versions
switch (name) {
case "TextView":
view = new AppCompatTextView(context, attrs);
break;
case "ImageView":
view = new AppCompatImageView(context, attrs);
break;
case "Button":
view = new AppCompatButton(context, attrs);
break;
case "EditText":
view = new AppCompatEditText(context, attrs);
break;
case "Spinner":
view = new AppCompatSpinner(context, attrs);
break;
case "ImageButton":
view = new AppCompatImageButton(context, attrs);
break;
case "CheckBox":
view = new AppCompatCheckBox(context, attrs);
break;
case "RadioButton":
view = new AppCompatRadioButton(context, attrs);
break;
case "CheckedTextView":
view = new AppCompatCheckedTextView(context, attrs);
break;
case "AutoCompleteTextView":
view = new AppCompatAutoCompleteTextView(context, attrs);
break;
case "MultiAutoCompleteTextView":
view = new AppCompatMultiAutoCompleteTextView(context, attrs);
break;
case "RatingBar":
view = new AppCompatRatingBar(context, attrs);
break;
case "SeekBar":
view = new AppCompatSeekBar(context, attrs);
break;
}
if (view == null) {
// If the original context does not equal our themed context, then we need to manually
// inflate it using the name so that android:theme takes effect.
view = createViewFromTag(context, name, attrs);
}
if (view != null) {
// If we have created a view, check it's android:onClick
checkOnClickListener(view, attrs);
}
return view;
}
private View createViewFromTag(Context context, String name, AttributeSet attrs) {
if (name.equals("view")) {
name = attrs.getAttributeValue(null, "class");
}
try {
mConstructorArgs[0] = context;
mConstructorArgs[1] = attrs;
if (-1 == name.indexOf('.')) {
// try the android.widget prefix first...
return createView(context, name, "android.widget.");
} else {
return createView(context, name, null);
}
} catch (Exception e) {
// We do not want to catch these, lets return null and let the actual LayoutInflater
// try
return null;
} finally {
// Don't retain references on context.
mConstructorArgs[0] = null;
mConstructorArgs[1] = null;
}
}
/**
* android:onClick doesn't handle views with a ContextWrapper context. This method
* backports new framework functionality to traverse the Context wrappers to find a
* suitable target.
*/
private void checkOnClickListener(View view, AttributeSet attrs) {
final Context context = view.getContext();
if (!ViewCompat.hasOnClickListeners(view) || !(context instanceof ContextWrapper)) {
// Skip our compat functionality if: the view doesn't have an onClickListener,
// or the Context isn't a ContextWrapper
return;
}
final TypedArray a = context.obtainStyledAttributes(attrs, sOnClickAttrs);
final String handlerName = a.getString(0);
if (handlerName != null) {
view.setOnClickListener(new DeclaredOnClickListener(view, handlerName));
}
a.recycle();
}
private View createView(Context context, String name, String prefix)
throws ClassNotFoundException, InflateException {
Constructor constructor = sConstructorMap.get(name);
try {
if (constructor == null) {
// Class not found in the cache, see if it's real, and try to add it
Class clazz = context.getClassLoader().loadClass(
prefix != null ? (prefix + name) : name).asSubclass(View.class);
constructor = clazz.getConstructor(sConstructorSignature);
sConstructorMap.put(name, constructor);
}
constructor.setAccessible(true);
return constructor.newInstance(mConstructorArgs);
} catch (Exception e) {
// We do not want to catch these, lets return null and let the actual LayoutInflater
// try
return null;
}
}
/**
* Allows us to emulate the {@code android:theme} attribute for devices before L.
*/
private static Context themifyContext(Context context, AttributeSet attrs,
boolean useAndroidTheme, boolean useAppTheme) {
final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.View, 0, 0);
int themeId = 0;
if (useAndroidTheme) {
// First try reading android:theme if enabled
themeId = a.getResourceId(R.styleable.View_android_theme, 0);
}
if (useAppTheme && themeId == 0) {
// ...if that didn't work, try reading app:theme (for legacy reasons) if enabled
themeId = a.getResourceId(R.styleable.View_theme, 0);
if (themeId != 0) {
Log.i(LOG_TAG, "app:theme is now deprecated. "
+ "Please move to using android:theme instead.");
}
}
a.recycle();
if (themeId != 0 && (!(context instanceof ContextThemeWrapper)
|| ((ContextThemeWrapper) context).getThemeResId() != themeId)) {
// If the context isn't a ContextThemeWrapper, or it is but does not have
// the same theme as we need, wrap it in a new wrapper
context = new ContextThemeWrapper(context, themeId);
}
return context;
}
/**
* An implementation of OnClickListener that attempts to lazily load a
* named click handling method from a parent or ancestor context.
*/
private static class DeclaredOnClickListener implements View.OnClickListener {
private final View mHostView;
private final String mMethodName;
private Method mResolvedMethod;
private Context mResolvedContext;
public DeclaredOnClickListener(@NonNull View hostView, @NonNull String methodName) {
mHostView = hostView;
mMethodName = methodName;
}
@Override
public void onClick(@NonNull View v) {
if (mResolvedMethod == null) {
resolveMethod(mHostView.getContext(), mMethodName);
}
try {
mResolvedMethod.invoke(mResolvedContext, v);
} catch (IllegalAccessException e) {
throw new IllegalStateException(
"Could not execute non-public method for android:onClick", e);
} catch (InvocationTargetException e) {
throw new IllegalStateException(
"Could not execute method for android:onClick", e);
}
}
@NonNull
private void resolveMethod(@Nullable Context context, @NonNull String name) {
while (context != null) {
try {
if (!context.isRestricted()) {
final Method method = context.getClass().getMethod(mMethodName, View.class);
if (method != null) {
mResolvedMethod = method;
mResolvedContext = context;
return;
}
}
} catch (NoSuchMethodException e) {
// Failed to find method, keep searching up the hierarchy.
}
if (context instanceof ContextWrapper) {
context = ((ContextWrapper) context).getBaseContext();
} else {
// Can't search up the hierarchy, null out and fail.
context = null;
}
}
final int id = mHostView.getId();
final String idText = id == View.NO_ID ? "" : " with id '"
+ mHostView.getContext().getResources().getResourceEntryName(id) + "'";
throw new IllegalStateException("Could not find method " + mMethodName
+ "(View) in a parent or ancestor Context for android:onClick "
+ "attribute defined on view " + mHostView.getClass() + idText);
}
}
}
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ParallaxViewPager parallaxVp = (ParallaxViewPager) findViewById(R.id.parallax_vp);
parallaxVp.attach(getSupportFragmentManager(),new int[]{R.layout.fragment_page_first,
R.layout.fragment_page_second,R.layout.fragment_page_third});
}
}
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