Question

前言：我对Android非常陌生。我环顾四周，阅读了大量的教程，我仍然没有把握这个概念。如果事情很简单，我会提前道歉。

我有一个活动正在使用Android Studio中模板的样板代码实现FragmentPagerAdapter。我的目标是在相同片段的各种实例之间切换以跟踪玩家得分（即，相同的布局，每个中的不同得分）。目前，我能够在看起来像是各种片段之间切换。我能够点击第一个片段上的按钮来计算分数，但是当我切换到下一个片段并单击一个按钮时，该片段中没有任何内容发生，但第一个片段的分数发生了变化。我认为这是因为它只使用一个片段而不是我需要的7个片段。如果你可以帮我弄清楚如何保存每个片段的分数，并且片段2上的按钮只会改变片段2上的分数。

这是我到目前为止所做的：

    package com.brbecker.tabletopcompanion.Games;


import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.v13.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.ViewGroup;
import com.brbecker.tabletopcompanion.MainActivity;
import com.brbecker.tabletopcompanion.R;

public class SwipeActivity extends Activity {
    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;

    // Supposed to be able to create multiple fragment instances and get at them again later.
    private SwipeTestFragment player1, player2, player3, player4, player5, player6, player7;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_swipe);
    // Create the adapter that will return a fragment for each of the three
    // primary sections of the activity.
    mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());

    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);
}


@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_swipe, menu);
    return true;
}

@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();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

然后是FragmentPagerAdapter类

public class SectionsPagerAdapter extends FragmentPagerAdapter {

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

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a SwipeTestFragment.

        return SwipeTestFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        // Show 7 total pages.
        return 7;
    }

    // This method is supposed to save a reference to a created Fragment.
    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        Fragment createdFragment = (Fragment) super.instantiateItem(container, position);
        switch (position) {
            case 0:
                player1 = (SwipeTestFragment) createdFragment;
                break;
            case 1:
                player2 = (SwipeTestFragment) createdFragment;
                break;
            case 2:
                player3 = (SwipeTestFragment) createdFragment;
                break;
            case 3:
                player4 = (SwipeTestFragment) createdFragment;
                break;
            case 4:
                player5 = (SwipeTestFragment) createdFragment;
                break;
            case 5:
                player6 = (SwipeTestFragment) createdFragment;
                break;
            case 6:
                player7 = (SwipeTestFragment) createdFragment;
                break;
        }
        return createdFragment;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "PLAYER 1";
            case 1:
                return "PLAYER 2";
            case 2:
                return "PLAYER 3";
            case 3:
                return "PLAYER 4";
            case 4:
                return "PLAYER 5";
            case 5:
                return "PLAYER 6";
            case 6:
                return "PLAYER 7";
        }
        return null;
    }
}

然后是片段代码：

public class SwipeTestFragment extends Fragment implements View.OnClickListener {

    // The fragment argument representing the section number for this fragment.
    private static final String ARG_SECTION_NUMBER = "section_number";

    public SwipeTestFragment() {
    }

    // Returns a new instance of this fragment for the given section number.
    public static SwipeTestFragment newInstance(int sectionNumber) {
        SwipeTestFragment fragment = new SwipeTestFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        setRetainInstance(true);
        View rootView = inflater.inflate(R.layout.fragment_swipe, container, false);

        //Set Page Title
        TextView playerHeading = (TextView) rootView.findViewById(R.id.playerHeading);
        String playerHeadingString = "Player " + getArguments().getInt(ARG_SECTION_NUMBER);
        playerHeading.setText(playerHeadingString);

        //This section sets up buttons.
        ImageButton minusone = (ImageButton) rootView.findViewById(R.id.minusBtn1);
        minusone.setOnClickListener(this);
        ImageButton plusone = (ImageButton) rootView.findViewById(R.id.plusBtn1);
        plusone.setOnClickListener(this);

        return rootView;
    }

    @Override
    public void onClick(View v) {
        TextView score = (TextView) getActivity().findViewById(R.id.scoreSevenWonders);
        TextView coins = (TextView) getActivity().findViewById(R.id.coinsSevenWonders);

        switch (v.getId()) {
            case R.id.minusBtn1:
                String presentvaluestring = coins.getText().toString();
                if (Integer.parseInt(presentvaluestring) > 0) {
                    int presentvalueint = Integer.parseInt(presentvaluestring);
                    presentvalueint--;
                    coins.setText(String.valueOf(presentvalueint));
                    if (presentvalueint % 3 == 2) {
                        setPlayerScore(-1, score);
                    }
                }
                break;
            case R.id.plusBtn1:
                presentvaluestring = coins.getText().toString();
                int presetvalueint = Integer.parseInt(presentvaluestring);
                presentvalueint++;
                if ((presentvalueint % 3) == 0) {
                    setPlayerScore(1, score);
                }
                coins.setText(String.valueOf(presentvalueint));
                break;                
        }
    }

    public TextView setPlayerScore(int increment, TextView total) {
        String totalstring = total.getText().toString();
        int totalint = Integer.parseInt(totalstring); //see if Integer.parseInt(total.getText().toString()) will work
        totalint += increment;
        total.setText(String.valueOf(totalint));
        return total;
    }
}

我认为它与getItem（）方法有关，但我不确定。如果有必要，我非常乐意提供额外的代码。

Answer 1

SwipeActivity.java

package com.brbecker.tabletopcompanion.Games;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.v13.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.ViewGroup;
import com.brbecker.tabletopcompanion.MainActivity;
import com.brbecker.tabletopcompanion.R;

public class SwipeActivity extends Activity  implements View.OnClickListener{
    private SectionsPagerAdapter mSectionsPagerAdapter;
    private ViewPager mViewPager;

    int[] scoresVal = new int[7];
    int[] coinsVal = new int[7];
    int current_pos = 0;
    TextView score;
    TextView coins;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_swipe);
    // Create the adapter that will return a fragment for each of the three
    // primary sections of the activity.
    mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());

    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);
    score = (TextView) findViewById(R.id.scoreSevenWonders);
    coins = (TextView) findViewById(R.id.coinsSevenWonders);

    ImageButton minusone = (ImageButton) findViewById(R.id.minusBtn1);
    minusone.setOnClickListener(this);
    ImageButton plusone = (ImageButton) findViewById(R.id.plusBtn1);
    plusone.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.minusBtn1:
                 int pos = viewpager.getCurrentItem();
                 presentvalueint = coinsVal[pos];
                 presentvalueint--;
                 if (presentvalueint % 3 == 2) {
                    score.setText(setPlayerScore(-1, pos));
                 }
                 coinsVal[pos] = presentvalueint;
                 coins.setText(String.valueOf(presentvalueint));
            break;
            case R.id.plusBtn1:
                 int pos = viewpager.getCurrentItem();
                 presentvalueint = coinsVal[pos];
                 presentvalueint++;
                 if (presentvalueint % 3 == 2) {
                     score.setText(setPlayerScore(-1, pos));
                 }
                 coinsVal[pos] = presentvalueint;
                 coins.setText(String.valueOf(presentvalueint));
            break;                
        }
    }

public String setPlayerScore(int increment, int pos) {


        scoresVal[pos] += increment;
        return String.valueOf(scoresVal[pos]);

}   


@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_swipe, menu);
    return true;
}

@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();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

<强> SectionsPagerAdapter.java

public class SectionsPagerAdapter extends FragmentPagerAdapter {


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

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a SwipeTestFragment.

        return SwipeTestFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        // Show 7 total pages.
        return 7;
    }


    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "PLAYER 1";
            case 1:
                return "PLAYER 2";
            case 2:
                return "PLAYER 3";
            case 3:
                return "PLAYER 4";
            case 4:
                return "PLAYER 5";
            case 5:
                return "PLAYER 6";
            case 6:
                return "PLAYER 7";
        }
        return null;
    }
}

<强> SwipeTestFragment.java

public class SwipeTestFragment extends Fragment{

// The fragment argument representing the section number for this fragment.
private static final String ARG_SECTION_NUMBER = "section_number";

public SwipeTestFragment() {
}

// Returns a new instance of this fragment for the given section number.
public static SwipeTestFragment newInstance(int sectionNumber) {
    SwipeTestFragment fragment = new SwipeTestFragment();
    Bundle args = new Bundle();
    args.putInt(ARG_SECTION_NUMBER, sectionNumber);
    fragment.setArguments(args);
    return fragment;
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    setRetainInstance(true);
    View rootView = inflater.inflate(R.layout.fragment_swipe, container, false);

    //Set Page Title
    TextView playerHeading = (TextView) rootView.findViewById(R.id.playerHeading);
    String playerHeadingString = "Player " + getArguments().getInt(ARG_SECTION_NUMBER);
    playerHeading.setText(playerHeadingString);


        return rootView;
    }

}

FragmentPagerAdapter难度大

1 个答案: