从 Main Activity 到 Fragment(ViewPager) 的按钮？

Question

所以我的 MainActivity 中有 2 个重要元素，一个按钮和一个编辑文本字段。我想让我的按钮只在第三个片段页面可见，该怎么做？这是我的代码。

DeviceFragment.java

package com.danmarker.decideforme;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

/**
 * Created by Laptop on 2015.03.17..
 */
public class DeviceFragment extends Fragment {

    public static final String ImageIDKey = "imagekey";
    public static final String DescriptionKey = "descriptionkey";


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_device, container, false);
        Bundle bundle = getArguments();


        if(bundle != null)
        {
            int imageID = bundle.getInt(ImageIDKey);
            String description = bundle.getString(DescriptionKey);

            setValues(view, imageID, description);
        }
        return view;
    }


private void setValues(View view, int imageID, String description) {
    ImageView imageView = (ImageView) view.findViewById(R.id.imageViewDevice);


    imageView.setImageResource(imageID);

    TextView textView = (TextView) view.findViewById(R.id.tvDeviceDescription);
    textView.setText(description);
}
}

DevicePagerAdaptor.java

package com.danmarker.decideforme;

import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

/**
 * Created by Laptop on 2015.03.18..
 */
public class DevicePagerAdaptor extends FragmentPagerAdapter {

    String[] devices;
    String[] deviceDescription;

    public DevicePagerAdaptor(FragmentManager fn, Context context) {
        super(fn);

        Resources resources = context.getResources();

        devices = resources.getStringArray(R.array.devices);
        deviceDescription = resources.getStringArray(R.array.device_description);

    }


    @Override
    public Fragment getItem(int position) {

        Bundle bundle = new Bundle();
        bundle.putString(DeviceFragment.DescriptionKey, deviceDescription[position]);
        bundle.putInt(DeviceFragment.ImageIDKey, getDeviceImageID(position));

        DeviceFragment deviceFragment = new DeviceFragment();
        deviceFragment.setArguments(bundle);

        return deviceFragment;
    }

    private int getDeviceImageID(int position) {

        int id = 0;
        switch (position) {


        }
        return id;

    }

    @Override
    public int getCount() {
        return devices.length;
    }

问题是，MainActivity 中的按钮覆盖在片段上，因此无论我如何滑动屏幕，它们都是可见的。我只想让它们可见，当我到达最后一个片段时。怎么做？我也有一个 fragment_device.xml，我必须在 DeviceFragment 中声明按钮，或者什么？谢谢！

Answer 1

如果您正在使用 ViewPager，您可以将 OnPageChangeListener 注册到您的 ViewPager 并使用 onPageSelected 方法来显示您的 Button。

viewPager.setOnPageChangeListener(new OnPageChangeListener() {

    @Override
    public void onPageSelected(int index) {
        if (index == 2) {
            button.setVisibility(View.VISIBLE);
        }else{
            button.setVisibility(View.GONE);
        }
    }

    @Override
    public void onPageScrolled(int arg0, float arg1, int arg2) {

    }

    @Override
    public void onPageScrollStateChanged(int arg0) {

    }
});

Answer 2

传递 bundle 参数中的位置，并根据您获得的位置在片段中显示按钮

从 Main Activity 到 Fragment(ViewPager) 的按钮？

Buttons from Main Activity to Fragment(ViewPage)?

android

fragment