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在MainActivity的片段中调用方法

android-tablayout android-recyclerview android-fragments android-studio android

BramH · 技术社区 · 6 年前

我的申请包括 MainActivity TabLayout . 第二个选项卡有一个 RecyclerView 允许通过单击来选择项目。初始状态如左图所示。但是,当选择一个或多个项目时,覆盖 Toolbar 显示的选项包括(从左到右)复制、编辑、删除或取消选择项目。这种情况显示在中图中。

例如,当选择“取消选择”选项时应隐藏并取消选择项目。问题是,我不知道如何让 ListAdapter 回收视图 知道应该取消选择这些项目。选择取消选择选项的当前结果如右图所示,因此 工具栏 隐藏但不会取消选择项目。

困难在于 回收视图 Fragment2 工具栏 主要活动 碎片2 deselect . 此方法工作正常,但我无法从 主要活动 .

为了解决这个问题,我尝试使用一个接口,但没有成功。第二种方法在下面提供的代码中实现。我正在打电话 取消选择 在 onOptionsItemSelected 方法,但它告诉我 fragment2 == null Dimitar Darazhanski fragment2 标签和在我的案例中使用的容器id。

如果您知道如何通过修改此方法或使用完全不同的方法来解决此问题,请让我知道!

主要活动

import android.animation.Animator;
import android.content.Intent;
import android.graphics.PorterDuff;
import android.os.Build;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.content.ContextCompat;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewAnimationUtils;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    ViewPager mViewPager;
    TabLayout tabLayout;
    Integer currentTab, fragmentID;
    boolean itemsSelected;

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


        mViewPager = findViewById(R.id.viewpager_main_activity);
        tabLayout = findViewById(R.id.tablayout_main_activity);
        tabLayout.setupWithViewPager(mViewPager);
        itemsSelected = false;

        displayDefaultAppbar();
        handleFragments(mViewPager);
        currentTab = handleStartupFragment(mViewPager, savedInstanceState);
    }

    private void displayDefaultAppbar() {
        final Toolbar toolbar = findViewById(R.id.toolbar_main_activity);
        TabLayout tabLayout = findViewById(R.id.tablayout_main_activity);
        setSupportActionBar(toolbar);
        if (getSupportActionBar() != null) {
            getSupportActionBar().setTitle(getResources().getString(R.string.app_name));
        }
        toolbar.setVisibility(View.VISIBLE);
        tabLayout.setVisibility(View.VISIBLE);
    }

    private void handleFragments(ViewPager mViewPager) {
        SectionsPagerAdapter mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
        mViewPager.setAdapter(mSectionsPagerAdapter);
        tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager) {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                super.onTabSelected(tab);
                int tabIconColor = ContextCompat.getColor(MainActivity.this, android.R.color.holo_red_dark);
                if(tab.getIcon() != null) {
                    tab.getIcon().setColorFilter(tabIconColor, PorterDuff.Mode.SRC_IN);
                }
                currentTab = tab.getPosition();
                handleToolbarOptions(currentTab);
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {
                super.onTabUnselected(tab);
                int tabIconColor = ContextCompat.getColor(MainActivity.this, android.R.color.black);
                if(tab.getIcon() != null) {
                    tab.getIcon().setColorFilter(tabIconColor, PorterDuff.Mode.SRC_IN);
                }
            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {
                super.onTabReselected(tab);
            }
        });
    }

    private Integer handleStartupFragment(ViewPager mViewPager, Bundle savedInstanceState) {
        Intent intent = getIntent();
        Integer startupFragment;
        tabLayout.getTabAt(0).setText("1");
        tabLayout.getTabAt(1).setText("2");
        tabLayout.getTabAt(2).setText("3");
        if(intent.hasExtra("initialFragment")){
            Bundle bd = getIntent().getExtras();
            startupFragment = bd.getInt("initialFragment");
        } else {
            startupFragment = 1;
        }
        if (savedInstanceState == null) {
            mViewPager.setCurrentItem(startupFragment);
        }
        return startupFragment;
    }

    @Override
    public void onAttachFragment(Fragment fragment) {
        super.onAttachFragment(fragment);
        fragmentID = fragment.getId();
    }

    private void handleToolbarOptions(Integer currentTab) {
        Toolbar toolbar = findViewById(R.id.toolbar_main_activity);
        if (currentTab == 1) {
            toolbar.getMenu().clear();
            toolbar.inflateMenu(R.menu.fragment2);
        } else {
            toolbar.getMenu().clear();
            toolbar.inflateMenu(R.menu.other);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        Toolbar toolbar = findViewById(R.id.toolbar_main_activity_selected);
        if (toolbar.isShown()) {
            getMenuInflater().inflate(R.menu.selected, menu);
        } else if (currentTab == 1) {
            getMenuInflater().inflate(R.menu.fragment2, menu);
        } else {
            getMenuInflater().inflate(R.menu.other, menu);
        }
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == R.id.selected_close) {
            if (findViewById(R.id.toolbar_main_activity_selected) != null) {
                hideSelectedToolbar();
                Fragment2 fragment2 = (Fragment2) getSupportFragmentManager().findFragmentById(R.id.tablayout_main_activity);
                if(fragment2 == null) {
                    Toast.makeText(this,"null",Toast.LENGTH_SHORT).show();
                } else if (!fragment2.isAdded()) {
                    Toast.makeText(this,"Not added",Toast.LENGTH_SHORT).show();
                } else {
                    fragment2.deselect();
                }
            }
            return true;
        } else {
            return super.onOptionsItemSelected(item);
        }
    }

    public void displaySelectedToolbar() {
        final Toolbar toolbar = findViewById(R.id.toolbar_main_activity_selected);
        toolbar.setVisibility(View.VISIBLE);
        if (Build.VERSION.SDK_INT >= 21) {
            toolbar.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
                @Override
                public void onLayoutChange(View view, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
                    Animator animator = ViewAnimationUtils.createCircularReveal(toolbar, toolbar.getWidth(), 0, 0,toolbar.getWidth());
                    animator.setDuration(ANIMATION_DURATION);
                    toolbar.removeOnLayoutChangeListener(this);
                    animator.start();
                }
            });
        }
        toolbar.setTitleTextColor(ContextCompat.getColor(MainActivity.this, android.R.color.black));
        setSupportActionBar(toolbar);
    }

    public void hideSelectedToolbar() {
        final Toolbar toolbar = findViewById(R.id.toolbar_main_activity_selected);
        if (Build.VERSION.SDK_INT >= 21) {
            Animator animator = ViewAnimationUtils.createCircularReveal(toolbar, toolbar.getWidth(), 0, toolbar.getWidth(), 0);
            animator.setDuration(ANIMATION_DURATION);
            animator.start();
            animator.addListener(new Animator.AnimatorListener() {
                @Override
                public void onAnimationStart(Animator animator) {

                }

                @Override
                public void onAnimationEnd(Animator animator) {
                    toolbar.setVisibility(View.GONE);
                    displayDefaultAppbar();
                }

                @Override
                public void onAnimationCancel(Animator animator) {

                }

                @Override
                public void onAnimationRepeat(Animator animator) {

                }
            });
        } else {
            toolbar.setVisibility(View.GONE);
            displayDefaultAppbar();
        }
    }

    private class SectionsPagerAdapter extends FragmentPagerAdapter {

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

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    return new Fragment1();
                case 1:
                    return new Fragment2();
                case 2:
                    return new Fragment3();
                default:
                    return null;
            }
        }

        @Override
        public int getCount() {
            return 3;
        }
    }
}

碎片2

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.TextView;
import java.util.ArrayList;

public class Fragment2 extends Fragment {

    ListAdapter adapter;
    RecyclerView rv;
    ArrayList<TestItem> list;
    Integer selected, selectedOld;

    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment2, container, false);

        selected = 0;
        selectedOld = 0;

        list = new ArrayList<>();
        list.add(new TestItem("Item 1",false));
        list.add(new TestItem("Item 2",false));
        list.add(new TestItem("Item 3",false));
        list.add(new TestItem("Item 4",false));
        list.add(new TestItem("Item 5",false));
        list.add(new TestItem("Item 6",false));

        rv = rootView.findViewById(R.id.rv_fragment2);
        adapter = new ListAdapter(getActivity());
        rv.setAdapter(adapter);
        rv.setLayoutManager(new LinearLayoutManager(getActivity()));

        return rootView;
    }

    private void handleToolbar() {
        if (selected == 1 && selectedOld == 0) {
            if (getActivity() != null) {
                ((MainActivity) getActivity()).displaySelectedToolbar();
            }
        } else if (selected == 0 && selectedOld == 1) {
            if (getActivity() != null) {
                ((MainActivity) getActivity()).hideSelectedToolbar();
            }
        }
    }

    public void deselect() {
        for (int i=0; i<list.size(); i++) {
            list.get(i).setSelected(false);
        }
        adapter.notifyDataSetChanged();
        rv.setAdapter(adapter);
    }
}

activity_main.xml

<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbarlayout_main_activity"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar_main_activity"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_collapseMode="pin"
            app:layout_scrollFlags="scroll|enterAlways|snap"
            android:background="?attr/colorPrimary"
            android:visibility="visible"/>

        <android.support.design.widget.TabLayout
            android:id="@+id/tablayout_main_activity"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

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

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager_main_activity"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar_main_activity_selected"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="@color/colorAccent"
        android:translationZ="4dp"
        android:visibility="invisible"/>

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

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="@+id/root_fragment2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv_fragment2"
        android:paddingTop="150dp"
        android:paddingBottom="10dp"
        android:paddingStart="10dp"
        android:paddingEnd="10dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"
        android:splitMotionEvents="false"
        android:clipToPadding="false"/>

</LinearLayout>

2 回复 | 直到 6 年前

Rumit Patel 6 年前

您可以使用的一个解决方案是 LocalBroadcastManager this question.

碎片2

private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            // you will be notified here, you can do your stuff(deselect) here
            String message = intent.getStringExtra("my_message");
            Log.d("receiver_message", "my_message = " + message);
        }
    };

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment2, container, false);

        LocalBroadcastManager.getInstance(getActivity()).registerReceiver(mMessageReceiver,
                new IntentFilter("my_event_tag"));

        return rootView;

    }

    @Override
    public void onDestroy() {
        LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(mMessageReceiver);
        super.onDestroy();
    }

private void callDeselectFromMainActivity() {
    Intent intent = new Intent("my_event_tag");
    intent.putExtra("my_message", "This is text should go to fragment...");
    LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}

当你打电话的时候方法自它应该叫 onReceive 方法

Oktawian 6 年前

您可以这样添加类:

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.view.ViewGroup;

public class MainTabsPagerAdapter extends FragmentStatePagerAdapter {

    int mNoOfTabs;

    private OneFragment oneFragment;
    private TwoFragment twoFragment;
    private ThreeFragment threeFragment;

    public MainTabsPagerAdapter(FragmentManager fm, int numberOfTabs) {
        super(fm);
        mNoOfTabs = numberOfTabs;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return new oneFragment();
            case 1:
                return new twoFragment();
            case 2:
                return new threeFragment();
        }
        return null;
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        Fragment createdFragment = (Fragment) super.instantiateItem(container, position);
        switch(position){
            case 0:
                oneFragment = (OneFragment) createdFragment;
                break;
            case(1):
                twoFragment = (TwoFragment) createdFragment;
                break;
            case(2):
                threeFragment = (ThreeFragment) createdFragment;
                break;
        }
        return createdFragment;
    }

    public OneFragment getOneFragment() {
        return oneFragment;
    }

    public TwoFragment getTwoFragment() {
        return twoFragment;
    }

    public ThreeFragment getThreeFragment() {
        return threeFragment;
    }

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

在此之后,添加您的主要活动:

@Override
protected void onCreate(Bundle savedInstanceState) {
    final String ONE_FRAGMENT = getString(R.string.one_fragment);
    final String TWO_FRAGMENT = getString(R.string.two_fragment);
    final String THREE_FRAGMENT = getString(R.string.three_fragment);

    mainTabLayout.addTab(mainTabLayout.newTab().setText(ONE_FRAGMENT));
    mainTabLayout.addTab(mainTabLayout.newTab().setText(TWO_FRAGMENT));
    mainTabLayout.addTab(mainTabLayout.newTab().setText(THREE_FRAGMENT));

    tabsPagerAdapter = new MainTabsPagerAdapter(getSupportFragmentManager(), mainTabLayout.getTabCount());
    mainViewPager.setAdapter(tabsPagerAdapter);
    mainViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mainTabLayout));
    mainTabLayout.addOnTabSelectedListener(this);
}

@Override
public void onTabSelected(TabLayout.Tab tab) {
    mainViewPager.setCurrentItem(tab.getPosition());
    mainToolbar.setTitle(firstCharToUpperCase(String.valueOf(tab.getText())));
}

@Override
public void onTabUnselected(TabLayout.Tab tab) {

}

@Override
public void onTabReselected(TabLayout.Tab tab) {

}

OneFragment oneFragment = tabsPagerAdapter.getOneFragment();
oneFragment.doSomething();