logcat的：
05-06 14:27:14.410: D/dalvikvm(2599): GC_FOR_ALLOC freed 93K, 6% free 3221K/3424K, paused 7ms, total 8ms
05-06 14:27:14.410: I/user(2599): dodano
05-06 14:27:14.474: D/libEGL(2599): loaded /system/lib/egl/libEGL_genymotion.so
05-06 14:27:14.478: D/(2599): HostConnection::get() New Host Connection established 0xb81a6b50, tid 2599
05-06 14:27:14.486: D/libEGL(2599): loaded /system/lib/egl/libGLESv1_CM_genymotion.so
05-06 14:27:14.486: D/libEGL(2599): loaded /system/lib/egl/libGLESv2_genymotion.so
05-06 14:27:14.530: W/EGL_genymotion(2599): eglSurfaceAttrib not implemented
05-06 14:27:14.534: E/OpenGLRenderer(2599): Getting MAX_TEXTURE_SIZE from GradienCache
05-06 14:27:14.534: E/OpenGLRenderer(2599): MAX_TEXTURE_SIZE: 16384
05-06 14:27:14.538: E/OpenGLRenderer(2599): Getting MAX_TEXTURE_SIZE from Caches::initConstraints()
05-06 14:27:14.538: E/OpenGLRenderer(2599): MAX_TEXTURE_SIZE: 16384
05-06 14:27:14.538: D/OpenGLRenderer(2599): Enabling debug mode 0
05-06 14:27:20.670: D/AndroidRuntime(2599): Shutting down VM
05-06 14:27:20.670: W/dalvikvm(2599): threadid=1: thread exiting with uncaught exception (group=0xa4d56b20)
05-06 14:27:20.670: E/AndroidRuntime(2599): FATAL EXCEPTION: main
05-06 14:27:20.670: E/AndroidRuntime(2599): Process: com.projectmidas.eduwords, PID: 2599
05-06 14:27:20.670: E/AndroidRuntime(2599): java.lang.NullPointerException
05-06 14:27:20.670: E/AndroidRuntime(2599): at com.projectmidas.eduwords.MainActivity$1.onClick(MainActivity.java:59)
05-06 14:27:20.670: E/AndroidRuntime(2599): at android.view.View.performClick(View.java:4438)
05-06 14:27:20.670: E/AndroidRuntime(2599): at android.view.View$PerformClick.run(View.java:18422)
05-06 14:27:20.670: E/AndroidRuntime(2599): at android.os.Handler.handleCallback(Handler.java:733)
05-06 14:27:20.670: E/AndroidRuntime(2599): at android.os.Handler.dispatchMessage(Handler.java:95)
05-06 14:27:20.670: E/AndroidRuntime(2599): at android.os.Looper.loop(Looper.java:136)
05-06 14:27:20.670: E/AndroidRuntime(2599): at android.app.ActivityThread.main(ActivityThread.java:5017)
05-06 14:27:20.670: E/AndroidRuntime(2599): at java.lang.reflect.Method.invokeNative(Native Method)
05-06 14:27:20.670: E/AndroidRuntime(2599): at java.lang.reflect.Method.invoke(Method.java:515)
05-06 14:27:20.670: E/AndroidRuntime(2599): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-06 14:27:20.670: E/AndroidRuntime(2599): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-06 14:27:20.670: E/AndroidRuntime(2599): at dalvik.system.NativeStart.main(Native Method)
Generator.java：
package com.projectmidas.eduwordsgeneratorbazy;
import java.io.File;
import java.io.IOException;
import de.greenrobot.daogenerator.DaoGenerator;
import de.greenrobot.daogenerator.Entity;
import de.greenrobot.daogenerator.Property;
import de.greenrobot.daogenerator.Schema;
public class Generator {
public static void main(String[] args) throws Exception {
Schema schema = makeSchema();
Entity user = schema.addEntity("User");
user.addLongProperty("id").primaryKey().autoincrement();
user.addStringProperty("email");
user.addStringProperty("password");
genereteDbSchema(schema, "../EduWords/src_db/");
}
private static Schema makeSchema() {
return new Schema(2, "com.projectmidas.eduwords.db");
}
private static void genereteDbSchema(Schema schema, String filePath)
throws Exception, IOException {
Util.deleteDirectory(new File(filePath), false);
new File(filePath).mkdirs();
new DaoGenerator().generateAll(schema, filePath);
}
private static class Util {
private static void deleteDirectory(File directory, boolean deleteRoot) {
if (directory.exists()) {
File[] files = directory.listFiles();
if (null != files) {
for (int i = 0; i < files.length; i++) {
if (files[i].isDirectory()) {
deleteDirectory(files[i], true);
} else {
files[i].delete();
}
}
}
}
if (deleteRoot) {
directory.delete();
}
}
}
}
MainActivity.java：
package com.projectmidas.eduwords;
import java.util.ArrayList;
import java.util.List;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import com.projectmidas.eduwords.db.DaoSession;
import com.projectmidas.eduwords.db.User;
public class MainActivity extends ActionBarActivity {
private DaoSession session;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button buttonUser = (Button) findViewById(R.id.user_button);
OnClickListener sendUser = new OnClickListener() {
@Override
public void onClick(View v) {
EditText email = (EditText) findViewById(R.id.tag_editText);
//stworzenie przykladowego usera
User user = new User();
//przypisanie mu mail
user.setEmail(email.getText().toString());
//dodanie do bazy
session.getUserDao().insert(user);
List<User> users = new ArrayList<User>();
users = session.getUserDao().queryBuilder().list();
for (User e: users){
Log.i("asdasd", e.getId() + e.getEmail());
}
}
};
buttonUser.setOnClickListener(sendUser);
}
@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;
}
}
答案 0 :(得分：5)
正如Manu所说，您的DaoSession session未初始化。
您可以使用以下代码获取会话：
SQLiteOpenHelper helper = new DaoMaster.DevOpenHelper(MainActivity.this, "MY_DB_NAME", null);
DaoMaster master = new DaoMaster(helper.getWritableDatabase());
session = master.newSession();
请记住，DevOpenHelper类仅用于测试目的。对于最终的应用程序，您应该扩展OpenHelper并在那里处理DB-schema-updates。即：
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.i(TAG, "Update DB-Schema: "+Integer.toString(oldVersion)+"->"+Integer.toString(newVersion));
switch (oldVersion) {
case 1:
db.execSQL("CREATE INDEX IF NOT EXISTS SOME_INDEX ON SOME_TABLE (SOME_COLUMN);");
// no break as we want to upgrade to the newest version.
case 2:
MyNewEntityDao.createTable(db, false);
// no break as we want to upgrade to the newest version.
default:
// Do some things you want to do on every update, i.e. send a message to a server.
break;
}
}
有关如何在具有多项活动的应用中使用greendao的详细信息，请参阅this post。
答案 1 :(得分：3)
非常简单的问题。您的
private DaoSession session;
未初始化，您需要执行类似
的操作private DaoMaster daoMaster = new DaoMaster(db);
private DaoSession session = daoMaster.newSession();