Android Api Demos登顶之路（三十六）Fragment-->Custom Animation

这个demo演示了如何利用setcustomAnimation实现Fragment的切换动画
* 实现自定义动画的类是ObjectAnimator，不仅用于fragment，也可用于view。
* 注意定义动画一定要replace方法之前执行.
* 动画资源文件需要放在res\animator\目录下，且根标签是set, objectAnimator, or valueAnimator三者之一。
activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <FrameLayout        android:id="@+id/frameLayout"        android:layout_width="match_parent"        android:layout_height="0dp"        android:layout_weight="1"         />    <LinearLayout         android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal"        android:gravity="center"        android:layout_marginBottom="5dp">        <Button             android:id="@+id/push"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Push"/>        <Button             android:id="@+id/pop"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Pop"/>    </LinearLayout></LinearLayout>

res目录下新建animator目录，定义动画效果
push_enter.xml

<?xml version="1.0" encoding="utf-8"?><set xmlns:android="http://schemas.android.com/apk/res/android" >    <objectAnimator         android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:valueFrom="300"        android:valueTo="0"        android:duration="3000"        android:propertyName="X">    </objectAnimator>    <objectAnimator         android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:valueFrom="0.0"        android:valueTo="1.0"        android:valueType="floatType"        android:duration="3000"        android:propertyName="alpha">    </objectAnimator></set>

push_exit.xml

<?xml version="1.0" encoding="utf-8"?><set xmlns:android="http://schemas.android.com/apk/res/android" >    <objectAnimator        android:duration="3000"        android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:propertyName="X"        android:valueFrom="0"        android:valueTo="300" >    </objectAnimator>    <objectAnimator        android:duration="3000"        android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:propertyName="alpha"        android:valueFrom="1.0"        android:valueTo="0.0"        android:valueType="floatType" >    </objectAnimator></set>

pop_enter.xml

<?xml version="1.0" encoding="utf-8"?><set xmlns:android="http://schemas.android.com/apk/res/android" >    <objectAnimator         android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:valueFrom="-300"        android:valueTo="0"        android:duration="3000"        android:propertyName="X">    </objectAnimator>    <objectAnimator         android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:valueFrom="0.0"        android:valueTo="1.0"        android:valueType="floatType"        android:duration="3000"        android:propertyName="alpha">    </objectAnimator></set>

pop_exit.xml

<?xml version="1.0" encoding="utf-8"?><set xmlns:android="http://schemas.android.com/apk/res/android" >    <objectAnimator        android:duration="3000"        android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:propertyName="X"        android:valueFrom="0"        android:valueTo="-300" >    </objectAnimator>    <objectAnimator        android:duration="3000"        android:interpolator="@android:anim/accelerate_decelerate_interpolator"        android:propertyName="alpha"        android:valueFrom="1.0"        android:valueTo="0.0"        android:valueType="floatType" >    </objectAnimator></set>

MainActivity

public class MainActivity extends Activity {    private int mStackLevel = 1;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Button push=(Button) findViewById(R.id.push);        Button pop=(Button) findViewById(R.id.pop);        push.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                addFragmentToStack();            }        });        pop.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                onBackPressed();            }        });        if(savedInstanceState==null){            FragmentTransaction ft=getFragmentManager().beginTransaction();            CountingFragment cf=CountingFragment.getInstance(mStackLevel);            ft.add(R.id.frameLayout, cf,"currentfragment");            ft.commit();        }else{            mStackLevel=savedInstanceState.getInt("stacklevel", 1);        }    }    @Override    public void onBackPressed() {        super.onBackPressed();    }    @Override    protected void onSaveInstanceState(Bundle outState) {        super.onSaveInstanceState(outState);        outState.putInt("stacklevel", mStackLevel);    }    protected void addFragmentToStack() {        mStackLevel++;        CountingFragment newFragment = CountingFragment                .getInstance(mStackLevel);        // 开启push事务则向activity中添加新的fragment        FragmentTransaction ft = getFragmentManager().beginTransaction();        // 设置自定义动画，前两个参数表示Fragment被推进任务栈时的动画效果        // 被两个参数表示Fragment被从任务栈推出时的动画效果        ft.setCustomAnimations(R.animator.push_enter, R.animator.push_exit,                R.animator.pop_enter, R.animator.pop_exit);        ft.replace(R.id.frameLayout, newFragment, "currentfragment");        /*         * 将事务添加到后台堆栈，当事务被提交后将执行事务，当从按返回键从堆栈中推出时则事务执行相反 的操作         */        ft.addToBackStack(null);        ft.commit();    }    public static class CountingFragment extends Fragment {        private int mNum;        public static CountingFragment getInstance(int num) {            CountingFragment cf = new CountingFragment();            Bundle args = new Bundle();            args.putInt("level", num);            cf.setArguments(args);            return cf;        }        @Override        public void onCreate(Bundle savedInstanceState) {            super.onCreate(savedInstanceState);            // 将传递进来的数据取出            Bundle args = getArguments();            mNum = args != null ? args.getInt("level") : 1;        }        @Override        public View onCreateView(LayoutInflater inflater, ViewGroup container,                Bundle savedInstanceState) {            // 使用取出的数据            View v = inflater.inflate(R.layout.hello, container, false);            TextView tv = (TextView) v.findViewById(R.id.text);            tv.setText("Fragment #:" + mNum);            tv.setBackground(getResources().getDrawable(                    android.R.drawable.gallery_thumb));            return v;        }    }}