展示多个fragment的Activiy，支持fragment之

传入需要展示的Fragment的class对象，通过反射方式创建Fragment对象展示，再次调用start(Context， Class<?>)方法启动，可以在原来的fragment上层再显示一个，返回键可以返回上个fragment。且有切换动画

package com.android.jsbcmasterapp.base;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.text.TextUtils;
import android.util.Log;

import com.android.jsbcmasterapp.R;
import com.android.jsbcmasterapp.Res;

/**
 * <pre>
 * Description: 展示activity用的宿主;
 * 调用{@link #start(Context, Class)}方法，传入需要展示的Fragment的class，
 * singleInstance启动模式，支持启动多次展示多个fragment支持返回
 *
 * Author: xucunyang
 * Time: 2021/3/4 15:45
 * </pre>
 */
public class FragmentDisplayActivity extends BaseCompatActivity {
    private static final String TAG = "FragmentDisplayActivity";

    private static final String KEY_FRAGMENT_NAME = "fragment_name";

    private FragmentManager fragmentManager;

    private String mFragmentPath;
    private FragmentTransaction mFragmentTransaction;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            mFragmentPath = getIntent().getStringExtra(KEY_FRAGMENT_NAME);
            fromNewIntent = false;
            super.onCreate(savedInstanceState);
        }
        Log.i(TAG, "onCreate: ");
    }

    @Override
    protected int getContentViews() {
        return R.layout.activity_display_fragment;
    }

    @Override
    protected void initViews() {}

    @Override
    protected void initListener() {}

    @Override
    protected void initData() {
        Log.i(TAG, "initData: ");
        if (TextUtils.isEmpty(mFragmentPath)) {
            Log.w(TAG, "initData: fragmentPath is empty");
            finish();
            return;
        }

        Log.i(TAG, "initData: show fragment:" + mFragmentPath);

        try {
            Class<?> clazz = Class.forName(mFragmentPath);
            fragment = (BaseFragment) clazz.newInstance();
            fragmentManager = getSupportFragmentManager();
            mFragmentTransaction = fragmentManager.beginTransaction();
            if (fromNewIntent) {
                mFragmentTransaction.setCustomAnimations(
                        R.anim.slide_enter,
                        R.anim.slide_exit,
                        R.anim.pop_left_enter,
                        R.anim.pop_left_exit
                );
            }
            mFragmentTransaction.replace(Res.getWidgetID("frame_layout"), fragment);
            mFragmentTransaction.addToBackStack(mFragmentPath);
            mFragmentTransaction.commit();
        } catch (ClassNotFoundException e) {
            Log.w(TAG, "initData: ClassNotFoundException:" + e.getMessage());
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            Log.w(TAG, "initData: IllegalAccessException:" + e.getMessage());
            e.printStackTrace();
        } catch (InstantiationException e) {
            Log.w(TAG, "initData: InstantiationException:" + e.getMessage());
            e.printStackTrace();
        }
    }

    private boolean fromNewIntent = false;

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);

        Log.i(TAG, "onNewIntent: " + intent);

        fromNewIntent = true;
        if (intent != null) {
            mFragmentPath = intent.getStringExtra(KEY_FRAGMENT_NAME);
            initData();
        } else {
            Log.i(TAG, "onNewIntent: intent is null");
        }
    }

    @Override
    public void onBackPressed() {
        Log.w(TAG, "onBackPressed: " + fragmentManager.getBackStackEntryCount());
        if (fragmentManager != null && fragmentManager.getBackStackEntryCount() == 1) {
            finish();
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public void finish() {
        FragmentManager fragmentManager = getSupportFragmentManager();
        mFragmentTransaction = fragmentManager.beginTransaction();
        mFragmentTransaction.setCustomAnimations(0, 0);
        mFragmentTransaction.commit();

        super.finish();

        overridePendingTransition(R.anim.pop_left_enter, R.anim.pop_left_exit);
    }

    @Override
    public void startActivity(Intent intent) {
        super.startActivity(intent);
        overridePendingTransition(R.anim.slide_enter, R.anim.activity_start_outgoing);
    }

    /**
     * 展示fragment
     *
     * @param context     上下文
     * @param fragmentCls fragment
     */
    public static void start(Context context, Class<? extends Fragment> fragmentCls) {
        if (fragmentCls != null) {
            Log.i(TAG, "start: " + fragmentCls.getName());
            Intent intent = new Intent(context, FragmentDisplayActivity.class);
            intent.putExtra(KEY_FRAGMENT_NAME, fragmentCls.getName());
            context.startActivity(intent);

            if (context instanceof Activity) {
                ((Activity) context).overridePendingTransition(R.anim.slide_enter, R.anim.activity_start_outgoing);
            } else {
                Log.w(TAG, "start: context is not instance of Activity, " + context);
            }
        } else {
            Log.w(TAG, "start: fragment is null");
        }
    }
}

使用的切换动画文件
activity_start_outgoing.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromXDelta="0%"
        android:toXDelta="-100%" />

    <alpha
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromAlpha="1.0"
        android:toAlpha="0.3" />

</set>

pop_left_enter.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromXDelta="-100%p"
        android:toXDelta="0%p" />

    <alpha
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromAlpha="0.3"
        android:toAlpha="1.0" />

</set>

pop_left_exit.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromXDelta="0%p"
        android:toXDelta="100%p" />

    <alpha
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromAlpha="1.0"
        android:toAlpha="0.3" />

</set>

slide_enter.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromXDelta="100%p"
        android:toXDelta="0%p" />

    <alpha
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromAlpha="0.3"
        android:toAlpha="1.0" />

</set>

slide_exit.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

    <translate
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromXDelta="0%"
        android:toXDelta="-100%" />

    <alpha
        android:duration="@android:integer/config_mediumAnimTime"
        android:fromAlpha="1.0"
        android:toAlpha="0.3" />

</set>