java - 如何以编程方式为主/详细信息流程设置“下一个”和“上一个”按钮

Question

我使用“主/详细信息流程” Activity 创建了一个示例应用。我已向详细 Activity 添加了两个按钮:下一步 和 上一步。如何以编程方式设置按钮操作，而不必在列表和详细信息之间来回切换？

item_detail.xml

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingStart="30dp"
        android:paddingEnd="30dp"
        android:weightSum="4"
        android:gravity="end"
        android:orientation="horizontal">

        <Button
            android:id="@+id/button_prev"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Prev"/>

        <Button
            android:id="@+id/button_next"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Next"/>
    </LinearLayout>

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:id="@+id/item_detail"
              style="?android:attr/textAppearanceLarge"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:padding="16dp"
              android:textIsSelectable="true"
              tools:context="co.test.app.sample.itemapplication.ItemDetailFragment"/>
</LinearLayout>

activity_item_detail.xml

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
                                                 xmlns:app="http://schemas.android.com/apk/res-auto"
                                                 xmlns:tools="http://schemas.android.com/tools"
                                                 android:layout_width="match_parent"
                                                 android:layout_height="match_parent"
                                                 android:fitsSystemWindows="true"
                                                 tools:context="co.test.app.sample.itemapplication.ItemDetailActivity"
                                                 tools:ignore="MergeRootFrame">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar"
        android:layout_width="match_parent"
        android:layout_height="@dimen/app_bar_height"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:toolbarId="@+id/toolbar">

            <android.support.v7.widget.Toolbar
                android:id="@+id/detail_toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>
        </android.support.design.widget.CollapsingToolbarLayout>

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

    <android.support.v4.widget.NestedScrollView
        android:id="@+id/item_detail_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

    </android.support.v4.widget.NestedScrollView>

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

DummyContent.java

package co.test.app.sample.itemapplication.dummy;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Helper class for providing sample content for user interfaces created by
 * Android template wizards.
 * <p>
 * TODO: Replace all uses of this class before publishing your app.
 */
public class DummyContent {

    /**
     * An array of sample (dummy) items.
     */
    public static final List<DummyItem> ITEMS = new ArrayList<DummyItem>();

    /**
     * A map of sample (dummy) items, by ID.
     */
    public static final Map<String, DummyItem> ITEM_MAP = new HashMap<String, DummyItem>();

    private static final int COUNT = 25;

    static {
        // Add some sample items.
        for (int i = 1; i <= COUNT; i++) {
            addItem(createDummyItem(i));
        }
    }

    private static void addItem(DummyItem item) {
        ITEMS.add(item);
        ITEM_MAP.put(item.id, item);
    }

    private static DummyItem createDummyItem(int position) {
        return new DummyItem(String.valueOf(position), "Item " + position, makeDetails(position));
    }

    private static String makeDetails(int position) {
        StringBuilder builder = new StringBuilder();
        builder.append("Details about Item: ").append(position);
        for (int i = 0; i < position; i++) {
            builder.append("\nMore details information here.");
        }
        return builder.toString();
    }

    /**
     * A dummy item representing a piece of content.
     */
    public static class DummyItem {
        public final String id;
        public final String content;
        public final String details;

        public DummyItem(String id, String content, String details) {
            this.id = id;
            this.content = content;
            this.details = details;
        }

        @Override
        public String toString() {
            return content;
        }
    }
}

ItemDetailActivity.java

package co.test.app.sample.itemapplication;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.ActionBar;
import android.view.MenuItem;

/**
 * An activity representing a single Item detail screen. This
 * activity is only used narrow width devices. On tablet-size devices,
 * item details are presented side-by-side with a list of items
 * in a {@link ItemListActivity}.
 */
public class ItemDetailActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_item_detail);
        Toolbar toolbar = (Toolbar) findViewById(R.id.detail_toolbar);
        setSupportActionBar(toolbar);

        // Show the Up button in the action bar.
        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.setDisplayHomeAsUpEnabled(true);
        }

        // savedInstanceState is non-null when there is fragment state
        // saved from previous configurations of this activity
        // (e.g. when rotating the screen from portrait to landscape).
        // In this case, the fragment will automatically be re-added
        // to its container so we don't need to manually add it.
        // For more information, see the Fragments API guide at:
        //
        // http://developer.android.com/guide/components/fragments.html
        //
        if (savedInstanceState == null) {
            // Create the detail fragment and add it to the activity
            // using a fragment transaction.
            Bundle arguments = new Bundle();
            arguments.putString(ItemDetailFragment.ARG_ITEM_ID,
                    getIntent().getStringExtra(ItemDetailFragment.ARG_ITEM_ID));
            ItemDetailFragment fragment = new ItemDetailFragment();
            fragment.setArguments(arguments);
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.item_detail_container, fragment)
                    .commit();
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == android.R.id.home) {
            // This ID represents the Home or Up button. In the case of this
            // activity, the Up button is shown. For
            // more details, see the Navigation pattern on Android Design:
            //
            // http://developer.android.com/design/patterns/navigation.html#up-vs-back
            //
            navigateUpTo(new Intent(this, ItemListActivity.class));
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

ItemListActivity.java

package co.test.app.sample.itemapplication;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;


import co.test.app.sample.itemapplication.dummy.DummyContent;

import java.util.List;

/**
 * An activity representing a list of Items. This activity
 * has different presentations for handset and tablet-size devices. On
 * handsets, the activity presents a list of items, which when touched,
 * lead to a {@link ItemDetailActivity} representing
 * item details. On tablets, the activity presents the list of items and
 * item details side-by-side using two vertical panes.
 */
public class ItemListActivity extends AppCompatActivity {

    /**
     * Whether or not the activity is in two-pane mode, i.e. running on a tablet
     * device.
     */
    private boolean mTwoPane;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        toolbar.setTitle(getTitle());

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        View recyclerView = findViewById(R.id.item_list);
        assert recyclerView != null;
        setupRecyclerView((RecyclerView) recyclerView);

        if (findViewById(R.id.item_detail_container) != null) {
            // The detail container view will be present only in the
            // large-screen layouts (res/values-w900dp).
            // If this view is present, then the
            // activity should be in two-pane mode.
            mTwoPane = true;
        }
    }

    private void setupRecyclerView(@NonNull RecyclerView recyclerView) {
        recyclerView.setAdapter(new SimpleItemRecyclerViewAdapter(DummyContent.ITEMS));
    }

    public class SimpleItemRecyclerViewAdapter
            extends RecyclerView.Adapter<SimpleItemRecyclerViewAdapter.ViewHolder> {

        private final List<DummyContent.DummyItem> mValues;

        public SimpleItemRecyclerViewAdapter(List<DummyContent.DummyItem> items) {
            mValues = items;
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.item_list_content, parent, false);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(final ViewHolder holder, int position) {
            holder.mItem = mValues.get(position);
            holder.mIdView.setText(mValues.get(position).id);
            holder.mContentView.setText(mValues.get(position).content);

            holder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (mTwoPane) {
                        Bundle arguments = new Bundle();
                        arguments.putString(ItemDetailFragment.ARG_ITEM_ID, holder.mItem.id);
                        ItemDetailFragment fragment = new ItemDetailFragment();
                        fragment.setArguments(arguments);
                        getSupportFragmentManager().beginTransaction()
                                .replace(R.id.item_detail_container, fragment)
                                .commit();
                    } else {
                        Context context = v.getContext();
                        Intent intent = new Intent(context, ItemDetailActivity.class);
                        intent.putExtra(ItemDetailFragment.ARG_ITEM_ID, holder.mItem.id);

                        context.startActivity(intent);
                    }
                }
            });
        }

        @Override
        public int getItemCount() {
            return mValues.size();
        }

        public class ViewHolder extends RecyclerView.ViewHolder {
            public final View mView;
            public final TextView mIdView;
            public final TextView mContentView;
            public DummyContent.DummyItem mItem;

            public ViewHolder(View view) {
                super(view);
                mView = view;
                mIdView = (TextView) view.findViewById(R.id.id);
                mContentView = (TextView) view.findViewById(R.id.content);
            }

            @Override
            public String toString() {
                return super.toString() + " '" + mContentView.getText() + "'";
            }
        }
    }
}

Answer 1

这是用于转发到详细信息页面的代码 fragment 。

 if (mTwoPane) {
                    Bundle arguments = new Bundle();
                    arguments.putString(ItemDetailFragment.ARG_ITEM_ID, holder.mItem.id);
                    ItemDetailFragment fragment = new ItemDetailFragment();
                    fragment.setArguments(arguments);
                    getSupportFragmentManager().beginTransaction()
                            .replace(R.id.item_detail_container, fragment)
                            .commit();
                } else {
                    Context context = v.getContext();
                    Intent intent = new Intent(context, ItemDetailActivity.class);
                    intent.putExtra(ItemDetailFragment.ARG_ITEM_ID, holder.mItem.id);

                    context.startActivity(intent);
                }

您可以通过更改arguments.putString(ItemDetailFragment.ARG_ITEM_ID,holder.mItem.id);的值转发到任何页面

在 next 和 prev 按钮的 onClick 事件中使用上述代码 fragment 。干杯:)