java - 如何在android中的viewpager上从右到左获取上一个 fragment

Question

我使用 viewpager 和 fragment 创建了一个 android 应用程序。我在 fragment 上使用两个按钮前进和后退。当我使用向前 Action 时，下一个 fragment 从右到左。这意味着 fragment 在这个 Action 中从右到左变化。

这是我的工作代码，

MainActivity.java

public class MainActivity extends FragmentActivity {

    private ViewPager viewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager=(ViewPager)findViewById(R.id.viewPager);
        viewPager.setAdapter(new MyPagerAdapter2(getSupportFragmentManager()));
        viewPager.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (viewPager.getCurrentItem() == 0) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 1) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 2) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 3) {
                    return true;
                }

                if (viewPager.getCurrentItem() == 4) {
                    return true;
                }

                return false;
            }
        });



    }

    private class MyPagerAdapter2 extends FragmentPagerAdapter {

        public MyPagerAdapter2(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int pos) {
            switch(pos) {

                case 0: return FirstFragment1.newInstance("FirstFragment_1");
                case 1: return SecondFragment1.newInstance("SecondFragment_1");
                case 2: return ThirdFragment1.newInstance("ThirdFragment_1");
                case 3: return FourthFragment1.newInstance("FourthFragment_1");
                case 4: return FifthFragment1.newInstance("FifthFragment_1");
                default: return FirstFragment1.newInstance("DefaultFragment_1");
            }
        }

        @Override
        public int getCount() {
            return 5;
        }
    }

    public void setCurrentItem(int which) {
        if(viewPager != null && which >= 0 && which <= 4) {
            viewPager.setCurrentItem(which);
        }
    }
}

FirstFragment1.java

public class FirstFragment1 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.first_frag_1, container, false);

        TextView tv = (TextView) v.findViewById(R.id.tvFragFirst);
        tv.setText(getArguments().getString("msg"));


        Button button1=(Button)v.findViewById(R.id.nextButton);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (getActivity() != null) {
                    ( (MainActivity)getActivity()).setCurrentItem(1); // fourth fragment index is 3
                }
            }
        });

        return v;
    }

    public static FirstFragment1 newInstance(String text) {

        FirstFragment1 f = new FirstFragment1();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if(isVisibleToUser) {
            Activity a = getActivity();
            if(a != null) a.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);
        }
    }

}

SecondFragment1.java

public class SecondFragment1 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.second_frag_1, container, false);

        TextView tv = (TextView) v.findViewById(R.id.tvFragSecond);
        tv.setText(getArguments().getString("msg"));


        Button button=(Button)v.findViewById(R.id.printButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if(getActivity() != null) {
                    ( (MainActivity)getActivity()).setCurrentItem(0); // second fragment index is 1


                }

            }
        });

        Button button1=(Button)v.findViewById(R.id.nextButton);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (getActivity() != null) {
                    ( (MainActivity)getActivity()).setCurrentItem(2); // fourth fragment index is 3


                }
            }
        });

        return v;
    }

    public static SecondFragment1 newInstance(String text) {

        SecondFragment1 f = new SecondFragment1();
        Bundle b = new Bundle();
        b.putString("msg", text);

        f.setArguments(b);

        return f;
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if(isVisibleToUser) {
            Activity a = getActivity();
            if(a != null) a.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LOCKED);
        }
    }

}

当我使用向后 Action 时，前一个 fragment 从左到右。但它应该是从右到左，我不知道该怎么做。

例如:-

当我点击 SecondFragment1 中的 button 时，FirstFragment1 应该在 viewpager 上从右到左出现.但目前它是从左到右。

我怎样才能做到这一点？我应该使用动画吗？

有什么想法吗？谢谢。

Answer 1

我建议您设置自定义过渡:

从右边进入:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
  <translate
     android:fromXDelta="100%" android:toXDelta="0%"
     android:fromYDelta="0%" android:toYDelta="0%"
     android:duration="500" />
</set>

向左退出:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
  <translate 
      android:fromXDelta="0%" android:toXDelta="-100%"
      android:fromYDelta="0%" android:toYDelta="0%"
      android:duration="500"/>
</set>

从左边进入:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
  <translate 
      android:fromXDelta="-100%" android:toXDelta="0%"
      android:fromYDelta="0%" android:toYDelta="0%"
      android:duration="500"/>
</set>

向右导出:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
  <translate
     android:fromXDelta="0%" android:toXDelta="100%"
     android:fromYDelta="0%" android:toYDelta="0%"
     android:duration="500" />
</set>

然后你可以这样设置转换:

fragmentTransaction.setCustomAnimations(R.anim.from_right, R.anim.to_left);

希望对你有帮助!