Android 渐变效果

点击查找按钮时会触发动画效果

页面布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            android:theme="@style/Base.AlertDialog.AppCompat"
            app:popupTheme="@style/AppTheme.PopupOverlay"
            app:title="@string/ToolBarName" />

    </android.support.design.widget.AppBarLayout>

    <TextView
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="@string/TxtContent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <ProgressBar
        android:id="@+id/loading_spinner"
        style="?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:indeterminate="false"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

</android.support.design.widget.CoordinatorLayout>

代码实现

public class MainActivity extends AppCompatActivity {

    private View mContentView;
    private View mLoadingView;
    private int mShortAnimationDuration;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB){
            Toolbar toolbar = findViewById(R.id.toolbar);
            setSupportActionBar(toolbar);
            mContentView = findViewById(R.id.content);
            mLoadingView = findViewById(R.id.loading_spinner);
            mContentView.setVisibility(View.GONE);//不占用布局
            mShortAnimationDuration = getResources().getInteger(android.R.integer.config_shortAnimTime);//获取动画默认时间
        }
     }
    private ShareActionProvider mShareActionProvider;
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        // Locate MenuItem with ShareActionProvider
        MenuItem item = menu.findItem(R.id.menu_item_share);

        // Fetch and store ShareActionProvider
        mShareActionProvider = (ShareActionProvider) MenuItemCompat.getActionProvider(item);

        // Return true to display menu
        return true;
    }
    // Call to update the share intent
    private void setShareIntent(Intent shareIntent) {
        if (mShareActionProvider != null) {
            mShareActionProvider.setShareIntent(shareIntent);
        }
    }    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        Intent pickContactIntent = new Intent(Intent.ACTION_PICK, Uri.parse("content://contacts"));
        pickContactIntent.setType(ContactsContract.CommonDataKinds.Phone.CONTENT_TYPE); // Show user only contacts w/ phone numbers
       // startActivityForResult(pickContactIntent, 1);
        this.setShareIntent(pickContactIntent);

        //noinspection SimplifiableIfStatement
        switch (id) {
            case R.id.action_settings:

                break;
            case R.id.app_bar_search:
                break;
            case R.id.menu_item_share://查找按钮触发动画
            {
                // Set the content view to 0% opacity but visible, so that it is visible
                // (but fully transparent) during the animation.
                mContentView.setAlpha(0f);
                mContentView.setVisibility(View.VISIBLE);
                // Animate the content view to 100% opacity, and clear any animation
                // listener set on the view.
                mContentView.animate().alpha(1f).setDuration(mShortAnimationDuration).setListener(null);
                // Animate the loading view to 0% opacity. After the animation ends,
                // set its visibility to GONE as an optimization step (it won't
                // participate in layout passes, etc.)
                mLoadingView.animate().alpha(0f).setDuration(mShortAnimationDuration).setListener(new AnimatorListenerAdapter() {
                            @Override
                            public void onAnimationEnd(Animator animation) {
                                mLoadingView.setVisibility(View.GONE);
                            }
                        });
            }
            break;
            default:
                break;
        }
        return super.onOptionsItemSelected(item);
    }
}