Question

你好:)希望你过得愉快。至于问题，我已经制作了一个导航抽屉并将片段添加到其中一个项目中，但点击菜单项不会显示片段，抽屉就会返回。对不起，如果有太多代码，只是想确保我不会错过任何东西:)这里是MainActivity.java：

package com.UntitledStudios.Xuinator2;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.FragmentManager;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import android.support.v4.app.Fragment;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    private final static String PACKAGE_NAME = "com.UntitledStudios.Xuinator2";
    SharedPreferences sharedPreferences;

    int count;

    ImageButton XuinaButton;
    Button ResetButton;
    ImageView MemeCornerAd;
    MediaPlayer Xsound;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        RateUs.app_launched(this);

        Xsound=MediaPlayer.create(MainActivity.this, R.raw.xuina2);
        MemeCornerAd = (ImageView) findViewById(R.id.imageView4);

        MemeCornerAd.setImageBitmap(getBitmapFromResources(getResources(), R.drawable.adviewpic));

        sharedPreferences = getSharedPreferences("count", Context.MODE_PRIVATE);
        count = sharedPreferences.getInt("count", Context.MODE_PRIVATE);

        TextView XuinaText = ((TextView) findViewById(R.id.HelloNick));
        XuinaText.setText("" + count);

        ClickActionCounter();

        ResetButtonAction();

        RedirMemeAd();
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, 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);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();
        BlankFragment fragment = null;
        if (id == R.id.rate) {
            /*final String appPackageName = getPackageName(); // package name of the app
            try {
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=" + appPackageName)));
            } catch (android.content.ActivityNotFoundException anfe) {
                startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=" + appPackageName)));
            }*/
        } else if (id == R.id.Contact) {

        } else if (id == R.id.AboutUs){
            fragment = new BlankFragment();
            FragmentManager fragmentManager = getSupportFragmentManager();
            fragmentManager.beginTransaction()
                    .replace(R.id.frame_container, fragment).commit();
        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    public static Bitmap getBitmapFromResources(Resources resources, int resImage) {
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = false;
        options.inDither = false;
        options.inSampleSize = 1;
        options.inScaled = false;
        options.inPreferredConfig = Bitmap.Config.ARGB_8888;

        return BitmapFactory.decodeResource(resources, resImage, options);
    }

    public void ClickActionCounter(){
        XuinaButton = (ImageButton) findViewById(R.id.Xuina);

        XuinaButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                try {
                    if (Xsound.isPlaying()) {
                        Xsound.stop();
                        Xsound.release();
                        Xsound = MediaPlayer.create(MainActivity.this, R.raw.xuina2);
                    } Xsound.start();
                } catch(Exception e) { e.printStackTrace(); }
                Context context = getApplicationContext();
                final Animation animScale;
                animScale = AnimationUtils.loadAnimation(context, R.anim.anim_scale);
                v.startAnimation(animScale);

                count++;
                TextView XuinaText = ((TextView) findViewById(R.id.HelloNick));
                XuinaText.setText("" + count);
                sharedPreferences.edit().putInt("count", count).apply();
            }

        });
    }

    public void ResetButtonAction(){
        ResetButton = (Button) findViewById(R.id.ResetButton);

        ResetButton.setOnClickListener(new View.OnClickListener(){

            @Override
            public void onClick(View v){
                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                builder.setPositiveButton("Yes", new DialogInterface.OnClickListener()
                {
                    @Override
                    public void onClick(DialogInterface dialog, int which)
                    {
                        count = 0;
                        TextView XuinaText = ((TextView) findViewById(R.id.HelloNick));
                        XuinaText.setText("" + count);
                        sharedPreferences.edit().putInt("count", count).apply();
                        Context context = getApplicationContext();
                        Toast.makeText(context, "Reset Successfully!", Toast.LENGTH_SHORT).show();                    }
                });
                builder.setNegativeButton("No", new DialogInterface.OnClickListener()
                {
                    @Override
                    public void onClick(DialogInterface dialog, int which)
                    {
                        // Stuff to do
                    }
                });

                builder.setMessage("Are you sure you want to reset the number of Xuinas?");
                builder.setTitle("Warning");

                AlertDialog d = builder.create();
                d.show();

            }
        });

    }

    public void RedirMemeAd(){
        MemeCornerAd.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                Intent intent = new Intent();
                intent.setAction(Intent.ACTION_VIEW);
                intent.addCategory(Intent.CATEGORY_BROWSABLE);
                intent.setData(Uri.parse("https://m.facebook.com/findmemecorner"));
                startActivity(intent);
            }
        });
    }
}

这里是BlankFragment.Java：

package com.UntitledStudios.Xuinator2;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class BlankFragment extends Fragment {

    public BlankFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_blank, container, false);
    }
}

这里是activity_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout 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:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"

        app:menu="@menu/activity_main_drawer" />

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:text="@string/rateus"/>

    </RelativeLayout>
</android.support.v4.widget.DrawerLayout>

这是content_main.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.UntitledStudios.Xuinator2.MainActivity"
    tools:showIn="@layout/app_bar_main">

    <TextView
        android:id="@+id/HelloNick"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="0"
        android:textSize="60sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.306" />

    <ImageButton
        android:id="@+id/Xuina"
        android:layout_width="463dp"
        android:layout_height="169dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:background="@null"
        android:scaleType="fitCenter"
        android:src="@mipmap/xuinalayer"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.496"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.738"
        tools:ignore="MissingConstraints" />

    <Button
        android:id="@+id/ResetButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Reset"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.167"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.982" />

    <ImageView
        android:id="@+id/imageView4"
        android:layout_width="247dp"
        android:layout_height="94dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:scaleType="centerCrop"
        android:src="@mipmap/adviewpic"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0" />

    <ImageButton
        android:id="@+id/imageButton"
        android:layout_width="85dp"
        android:layout_height="78dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:background="@null"
        android:scaleType="fitCenter"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.675"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="1.0"
        app:srcCompat="@mipmap/reverse" />

    <TextView
        android:id="@+id/REVERSE"
        android:layout_width="91dp"
        android:layout_height="31dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Reverse"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.898" />

    <TextView
        android:id="@+id/Reverses"
        android:layout_width="55dp"
        android:layout_height="38dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="X0"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.934"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="1.0" />

    <RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        tools:context="com.above_inc.shyam.drawer.MainActivity"
        tools:showIn="@layout/app_bar_main">


        <FrameLayout
            android:id="@+id/frame_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />
    </RelativeLayout>
</android.support.constraint.ConstraintLayout>

和fragment_blank.xml：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.UntitledStudios.Xuinator2.BlankFragment">

    <!-- TODO: Update blank fragment layout -->

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_blank_fragment" />
</FrameLayout>

Answer 1

更改您的fragment_blank.xml :(您可以使用LinearLayout，RelativeLayout等除FrameLayout外）

public class matrixIni {
    private int row;
    private int col;    
    private String matrix[][];

    //constructor for calss matricDec
    public matrixIni(int row, int col){
        this.row = row;
        this.col = col;
        matrix[][] = new String[row][col]

        //matrix[1][1] = "test";
         //System.out.println(matrix[1][1]);
    }
}

Answer 2

一切似乎都很好。尝试更改片段的布局

<android.support.constraint.ConstraintLayout 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">

<!-- TODO: Update blank fragment layout -->

<TextView
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    text"Hello WOrld"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@id/toolbar_social_login"/>

导航抽屉片段没有显示

2 个答案: