应用程序在首次运行API 26时崩溃

时间：2018-02-12 21:26:43

标签： java android database

我在资源文件夹中创建了一个带数据库的应用。我写了一个代码将数据库复制到SD卡，当然对于android 6 +它需要运行时权限。我的问题：应用程序在请求权限之前复制数据库所以第一次应用程序崩溃但是权限窗口在屏幕上，如果你允许它在第二次运行应用程序就像魅力。请帮我解决这个问题。

这是我的代码：

package farmani.com.essentialwordsforielts.mainPage;

import android.Manifest;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Build;
import android.os.Environment;
import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.design.widget.TabLayout;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import farmani.com.essentialwordsforielts.R;

public class MainActivity extends AppCompatActivity  {

public static Context context;
DrawerLayout drawerLayout;
NavigationView navigationView;
ImageView hamburger;
SQLiteDatabase database;
String destPath;

public static ArrayList<Structure> list = new ArrayList<Structure>();
public static ArrayList<Structure> favorite = new ArrayList<Structure>();

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

    if(Build.VERSION.SDK_INT >= 23){


        if(ContextCompat.checkSelfPermission(MainActivity.this, 
Manifest.permission.READ_EXTERNAL_STORAGE) != 
PackageManager.PERMISSION_GRANTED){

            ActivityCompat.requestPermissions(MainActivity.this
                    , new String[]{Manifest.permission.READ_EXTERNAL_STORAGE
                            ,Manifest.permission.WRITE_EXTERNAL_STORAGE}
                    , 1);

        }else if(ContextCompat.checkSelfPermission(MainActivity.this, 
Manifest.permission.WRITE_EXTERNAL_STORAGE) != 
PackageManager.PERMISSION_GRANTED){

            ActivityCompat.requestPermissions(MainActivity.this
                    , new String[]{Manifest.permission.READ_EXTERNAL_STORAGE
                            ,Manifest.permission.WRITE_EXTERNAL_STORAGE}
                    , 1);

        }else {

            Toast.makeText(MainActivity.this,"You grandet 
earlier",Toast.LENGTH_LONG).show();

        }


    }





    try {
        destPath = 
Environment.getExternalStorageDirectory().getAbsolutePath() + "/ielts/";
        File file = new File(destPath);
        if (!file.exists()) {
            file.mkdirs();
            file.createNewFile();
            CopyDB(getBaseContext().getAssets().open("md_book.db"),
                    new FileOutputStream(destPath + "/md_book.db"));
        }
    } catch (IOException e1) {
        e1.printStackTrace();
    }

    context = getApplicationContext();
    setTabOption();

    drawerLayout = findViewById(R.id.navigation_drawer);
    navigationView = findViewById(R.id.navigation_view);
    hamburger = findViewById(R.id.hamburger);
    hamburger.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            drawerLayout.openDrawer(Gravity.START);
        }
    });




    navigationView.setNavigationItemSelectedListener(new 
NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            int id = item.getItemId();
            if (id == R.id.exit) {
                AlertDialog.Builder alertDialog = new AlertDialog.Builder(
                        MainActivity.this);

                alertDialog.setTitle(R.string.exit);

                alertDialog.setMessage(R.string.exit_ask);
                alertDialog.setCancelable(false);

                alertDialog.setPositiveButton(R.string.yes,
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int 
which) {
                                finish();
                            }
                        });

                alertDialog.setNegativeButton(R.string.no,
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int 
which) {

                                dialog.cancel();
                            }
                        });

                alertDialog.show();
            }

            return true;
        }
    });

    selectList();
    selectFavorite();


}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] 
permissions, @NonNull int[] grantResults) {

    switch (requestCode) {
        case 1: {

            if (grantResults.length >= 2 && grantResults[0] == 
PackageManager.PERMISSION_GRANTED && grantResults[1] == 
PackageManager.PERMISSION_GRANTED) {

                Toast.makeText(MainActivity.this, "Access granted", 
Toast.LENGTH_LONG).show();

            }

        }
    }
}


@Override
public void onBackPressed() {
    if (drawerLayout.isDrawerOpen(Gravity.START)) {
        drawerLayout.closeDrawer(Gravity.START);
    } else {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(
                MainActivity.this);

        alertDialog.setTitle(R.string.exit);

        alertDialog.setMessage(R.string.exit_ask);
        alertDialog.setCancelable(false);

        alertDialog.setPositiveButton(R.string.yes,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                    }
                });

        alertDialog.setNegativeButton(R.string.no,
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {

                        dialog.cancel();
                    }
                });

        alertDialog.show();
    }
}


private void setTabOption() {
    ViewPager viewPager = findViewById(R.id.viewpager);
    viewPager.setAdapter(new AdapterFragment(getSupportFragmentManager(), 
context));
    TabLayout tabStrip = findViewById(R.id.tabs);
    tabStrip.setupWithViewPager(viewPager);
}

private void CopyDB(InputStream inputStream, OutputStream outputStream) 
throws IOException {
    byte[] buffer = new byte[1024];
    int length;
    while ((length = inputStream.read(buffer)) > 0) {
        outputStream.write(buffer, 0, length);
    }
    inputStream.close();
    outputStream.close();
}

private void selectFavorite(){

    database = SQLiteDatabase.openOrCreateDatabase(destPath + "/md_book.db", 
null);
    Cursor cursor = database.rawQuery("SELECT * FROM main WHERE fav = 1", 
null);
    while (cursor.moveToNext()){
        String word = cursor.getString(cursor.getColumnIndex("word"));
        String definition = 
cursor.getString(cursor.getColumnIndex("definition"));
        String trans = cursor.getString(cursor.getColumnIndex("trans"));
        String img = cursor.getString(cursor.getColumnIndex("img"));
        int id = cursor.getInt(cursor.getColumnIndex("id"));

        Structure struct = new Structure(word, definition, trans, img, id);
        struct.setWord(word);
        struct.setDefinition(definition);
        struct.setTrans(trans);
        struct.setImg(img);
        struct.setId(id);
        favorite.add(struct);
    }

}

private void selectList(){

    database = SQLiteDatabase.openOrCreateDatabase(destPath + "/md_book.db", 
null);
    Cursor cursor = database.rawQuery("SELECT * FROM main", null);
    while (cursor.moveToNext()){
        String word = cursor.getString(cursor.getColumnIndex("word"));
        String definition = 
cursor.getString(cursor.getColumnIndex("definition"));
        String trans = cursor.getString(cursor.getColumnIndex("trans"));
        String img = cursor.getString(cursor.getColumnIndex("img"));
        int id = cursor.getInt(cursor.getColumnIndex("id"));

        Structure struct = new Structure(word, definition, trans, img, id);
        struct.setWord(word);
        struct.setDefinition(definition);
        struct.setTrans(trans);
        struct.setImg(img);
        struct.setId(id);
        list.add(struct);
    }

    }

}

1 个答案:

答案 0 :(得分：0)

这很简单。将您的Copy DB代码移动到权限授予处理。如果您在获得许可之前在onCreate中执行此操作，则会崩溃。祝你好运。

package farmani.com.essentialwordsforielts.mainPage; 

        import android.Manifest;
        import android.content.Context;
        import android.content.DialogInterface;
        import android.content.pm.PackageManager;
        import android.database.Cursor;
        import android.database.sqlite.SQLiteDatabase;
        import android.os.Build;
        import android.os.Environment;
        import android.support.annotation.NonNull;
        import android.support.design.widget.NavigationView;
        import android.support.design.widget.TabLayout;
        import android.support.v4.app.ActivityCompat;
        import android.support.v4.content.ContextCompat;
        import android.support.v4.view.ViewPager;
        import android.support.v4.widget.DrawerLayout;
        import android.support.v7.app.AlertDialog;
        import android.support.v7.app.AppCompatActivity;
        import android.os.Bundle;
        import android.view.Gravity;
        import android.view.MenuItem;
        import android.view.View;
        import android.widget.ImageView;
        import android.widget.Toast;
        import java.io.File;
        import java.io.FileOutputStream;
        import java.io.IOException;
        import java.io.InputStream;
        import java.io.OutputStream;
        import java.util.ArrayList;
        import farmani.com.essentialwordsforielts.R;

public class MainActivity extends AppCompatActivity {

    public static Context context;
    DrawerLayout drawerLayout;
    NavigationView navigationView;
    ImageView hamburger;
    SQLiteDatabase database;
    String destPath;

    public static ArrayList<Structure> list = new ArrayList<Structure>();
    public static ArrayList<Structure> favorite = new ArrayList<Structure>();

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

        if(Build.VERSION.SDK_INT >= 23){


            if(ContextCompat.checkSelfPermission(MainActivity.this,
                    Manifest.permission.READ_EXTERNAL_STORAGE) !=
                    PackageManager.PERMISSION_GRANTED){

                ActivityCompat.requestPermissions(MainActivity.this
                        , new String[]{Manifest.permission.READ_EXTERNAL_STORAGE
                                ,Manifest.permission.WRITE_EXTERNAL_STORAGE}
                        , 1);

            }else if(ContextCompat.checkSelfPermission(MainActivity.this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE) !=
                    PackageManager.PERMISSION_GRANTED){

                ActivityCompat.requestPermissions(MainActivity.this
                        , new String[]{Manifest.permission.READ_EXTERNAL_STORAGE
                                ,Manifest.permission.WRITE_EXTERNAL_STORAGE}
                        , 1);

            }else {

                Toast.makeText(MainActivity.this,"You grandet 
                        earlier",Toast.LENGTH_LONG).show();

            }


        }

        context = getApplicationContext();
        setTabOption();

        drawerLayout = findViewById(R.id.navigation_drawer);
        navigationView = findViewById(R.id.navigation_view);
        hamburger = findViewById(R.id.hamburger);
        hamburger.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                drawerLayout.openDrawer(Gravity.START);
            }
        });







    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 1: {

                if (grantResults.length >= 2 && grantResults[0] ==
                        PackageManager.PERMISSION_GRANTED && grantResults[1] ==
                        PackageManager.PERMISSION_GRANTED) {

                   setupDB();
                   setupNavDrawer();

                    Toast.makeText(MainActivity.this, "Access granted",
                            Toast.LENGTH_LONG).show();

                }

            }
        }
    }


    @Override
    public void onBackPressed() {
        if (drawerLayout.isDrawerOpen(Gravity.START)) {
            drawerLayout.closeDrawer(Gravity.START);
        } else {
            AlertDialog.Builder alertDialog = new AlertDialog.Builder(
                    MainActivity.this);

            alertDialog.setTitle(R.string.exit);

            alertDialog.setMessage(R.string.exit_ask);
            alertDialog.setCancelable(false);

            alertDialog.setPositiveButton(R.string.yes,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
                            finish();
                        }
                    });

            alertDialog.setNegativeButton(R.string.no,
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {

                            dialog.cancel();
                        }
                    });

            alertDialog.show();
        }
    }


    private void setTabOption() {
        ViewPager viewPager = findViewById(R.id.viewpager);
        viewPager.setAdapter(new AdapterFragment(getSupportFragmentManager(),
                context));
        TabLayout tabStrip = findViewById(R.id.tabs);
        tabStrip.setupWithViewPager(viewPager);
    }

    private void setupDB(){
        try {
            destPath =
                    Environment.getExternalStorageDirectory().getAbsolutePath() + "/ielts/";
            File file = new File(destPath);
            if (!file.exists()) {
                file.mkdirs();
                file.createNewFile();
                CopyDB(getBaseContext().getAssets().open("md_book.db"),
                        new FileOutputStream(destPath + "/md_book.db"));
            }
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }
    private void setupNavDrawer(){
        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                int id = item.getItemId();
                if (id == R.id.exit) {
                    AlertDialog.Builder alertDialog = new AlertDialog.Builder(
                            MainActivity.this);

                    alertDialog.setTitle(R.string.exit);

                    alertDialog.setMessage(R.string.exit_ask);
                    alertDialog.setCancelable(false);

                    alertDialog.setPositiveButton(R.string.yes,
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int
                                        which) {
                                    finish();
                                }
                            });

                    alertDialog.setNegativeButton(R.string.no,
                            new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int
                                        which) {

                                    dialog.cancel();
                                }
                            });

                    alertDialog.show();
                }

                return true;
            }
        });

        selectList();
        selectFavorite();
    }

    private void CopyDB(InputStream inputStream, OutputStream outputStream)
            throws IOException {
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, length);
        }
        inputStream.close();
        outputStream.close();
    }

    private void selectFavorite(){

        database = SQLiteDatabase.openOrCreateDatabase(destPath + "/md_book.db",
                null);
        Cursor cursor = database.rawQuery("SELECT * FROM main WHERE fav = 1",
                null);
        while (cursor.moveToNext()){
            String word = cursor.getString(cursor.getColumnIndex("word"));
            String definition =
                    cursor.getString(cursor.getColumnIndex("definition"));
            String trans = cursor.getString(cursor.getColumnIndex("trans"));
            String img = cursor.getString(cursor.getColumnIndex("img"));
            int id = cursor.getInt(cursor.getColumnIndex("id"));

            Structure struct = new Structure(word, definition, trans, img, id);
            struct.setWord(word);
            struct.setDefinition(definition);
            struct.setTrans(trans);
            struct.setImg(img);
            struct.setId(id);
            favorite.add(struct);
        }

    }

    private void selectList(){

        database = SQLiteDatabase.openOrCreateDatabase(destPath + "/md_book.db",
                null);
        Cursor cursor = database.rawQuery("SELECT * FROM main", null);
        while (cursor.moveToNext()){
            String word = cursor.getString(cursor.getColumnIndex("word"));
            String definition =
                    cursor.getString(cursor.getColumnIndex("definition"));
            String trans = cursor.getString(cursor.getColumnIndex("trans"));
            String img = cursor.getString(cursor.getColumnIndex("img"));
            int id = cursor.getInt(cursor.getColumnIndex("id"));

            Structure struct = new Structure(word, definition, trans, img, id);
            struct.setWord(word);
            struct.setDefinition(definition);
            struct.setTrans(trans);
            struct.setImg(img);
            struct.setId(id);
            list.add(struct);
        }

    }

}
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