帮我解决这个问题。我仍然坚持这一个。我真的不明白怎么做。我是新学习Java，这是我第一次构建apk。 无法打开固定应用程序中的数据库。我有三个水龙头。主菜单， search1，search2 。标签搜索都没有工作（不幸的是app停止了）。但我可以在主菜单上解锁按钮。
当我在oncreate中调用initUi方法时。它没有用。主菜单和标签搜索中的我的按钮无法打开。
当我运行我的应用程序时，这是我的LogCat，而不是单击search1
02-26 12:16:50.141: E/AndroidRuntime(1090): FATAL EXCEPTION: main
02-26 12:16:50.141: E/AndroidRuntime(1090): Process: com.rdsj.land, PID: 1090
02-26 12:16:50.141: E/AndroidRuntime(1090): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.rdsj.land/com.rdsj.land.keterangan}: java.lang.NullPointerException
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.ActivityThread.startActivityNow(ActivityThread.java:2035)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:135)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:347)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:749)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.widget.TabHost.setCurrentTab(TabHost.java:413)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.widget.TabHost$2.onTabSelectionChanged(TabHost.java:154)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.widget.TabWidget$TabClickListener.onClick(TabWidget.java:546)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.view.View.performClick(View.java:4438)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.view.View$PerformClick.run(View.java:18422)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.os.Handler.handleCallback(Handler.java:733)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.os.Handler.dispatchMessage(Handler.java:95)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.os.Looper.loop(Looper.java:136)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.ActivityThread.main(ActivityThread.java:5017)
02-26 12:16:50.141: E/AndroidRuntime(1090): at java.lang.reflect.Method.invokeNative(Native Method)
02-26 12:16:50.141: E/AndroidRuntime(1090): at java.lang.reflect.Method.invoke(Method.java:515)
02-26 12:16:50.141: E/AndroidRuntime(1090): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
02-26 12:16:50.141: E/AndroidRuntime(1090): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
02-26 12:16:50.141: E/AndroidRuntime(1090): at dalvik.system.NativeStart.main(Native Method)
02-26 12:16:50.141: E/AndroidRuntime(1090): Caused by: java.lang.NullPointerException
02-26 12:16:50.141: E/AndroidRuntime(1090): at com.rdsj.aircraft.keterangan.checkResult(keterangan.java:101)
02-26 12:16:50.141: E/AndroidRuntime(1090): at com.rdsj.aircraft.keterangan.onCreate(keterangan.java:77)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.Activity.performCreate(Activity.java:5231)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
02-26 12:16:50.141: E/AndroidRuntime(1090): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
02-26 12:16:50.141: E/AndroidRuntime(1090): ... 18 more
这是我的Keterangan.Java
package com.rdsj.land;
import android.app.Activity;
import android.app.AlertDialog;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.preference.PreferenceManager;
import android.speech.tts.TextToSpeech;
import android.view.View;
import android.webkit.WebView;
import android.widget.Button;
import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.rdsj.land.R;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.util.Patterns;
import android.util.TypedValue;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.Window;
import android.view.WindowManager.LayoutParams;
import android.widget.TextView;
import android.widget.Toast;
public class keterangan extends Activity implements TextToSpeech.OnInitListener {
final static int SEMUA = 1;
final static int CARI = 2;
final static int ROUNDLE = 3;
final String[] dict_name = new String[] {"SEMUA","CARI", "ROUNDLE"};
private int DICT;
private String text;
private SQLiteDatabase db = null;
private Cursor catatan = null;
private DBPesawat db_pesawat_helper;
private TextToSpeech mTts;
private int SpeechStatus;
private float font_size;
TextView title, content;
Button speech, close;
WebView pic;
Handler handler = new Handler();
Thread searching;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
/* Get Intent Parameter */
this.getIntentParameter();
/* Open Database File */
db_pesawat_helper = new DBPesawat(this);
try {
db_pesawat_helper.openDataBase();
db = db_pesawat_helper.getReadableDatabase();
}catch(SQLException sqle){
throw sqle;
}
/* UI Initialization */ //null pointer in this line
if (checkResult()) this.initUI();
}
private void getIntentParameter() {
// TODO Auto-generated method stub
Uri data = this.getIntent().getData();
if (data!=null) {
DICT = Integer.parseInt(data.getQueryParameter("dict"));
text = data.getQueryParameter("text");
} else {
DICT = this.getIntent().getExtras().getInt("DICT", 1);
text = this.getIntent().getExtras().getString("TEXT");
}
}
private boolean checkResult() {
// TODO Auto-generated method stub
String catatan1;
switch(DICT) {
default:
case SEMUA:
catatan1 = "SELECT ringkasan FROM Main where lower(Type)=lower('"+text.replace("'", "''")+"') ";
break;
case CARI:
catatan1 = "SELECT * FROM Cari where lower(Nama_Pesawat)=lower('"+text.replace("'", "''")+"')"; // And this line null pointer too
break;
case ROUNDLE:
catatan1 = "SELECT * FROM Roundle where lower(Negara)=lower('"+text.replace("'", "''")+"')"; // This one too when I click on tab search Roundle
break;
}
catatan = db.rawQuery(catatan1, null);
if (!catatan.moveToFirst()) {
Toast.makeText(this, "word `"+text+"` not found in "+dict_name[DICT-1]+" dictionary !", Toast.LENGTH_SHORT).show();
this.finish();
return false;
} else return true;
}
private void initUI() {
// TODO Auto-generated method stub
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.setContentView(R.layout.keterangan);
this.getWindow().setLayout(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
mTts = new TextToSpeech(this,this);
title = (TextView) findViewById(R.id.title);
content = (TextView) findViewById(R.id.content);
speech = (Button) findViewById(R.id.speech);
close = (Button) findViewById(R.id.close);
pic = (WebView) findViewById(R.id.tampil);
/* Define event callback function */
speech.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
if (SpeechStatus == TextToSpeech.LANG_MISSING_DATA || SpeechStatus == TextToSpeech.LANG_NOT_SUPPORTED)
installLanguage();
else
mTts.speak(text, TextToSpeech.QUEUE_FLUSH, null);
}
});
close.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
keterangan.this.finish();
}
});
}
private boolean isValidUrl(String url) {
Pattern p = Patterns.WEB_URL;
Matcher m = p.matcher(url);
if(m.matches())
return true;
else
return false;
}
@Override
public void onStart() {
super.onStart();
/* Get Preferences */
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
font_size = Float.parseFloat(prefs.getString("font_size", "18"));
/* Display Result */
title.setText(text);
content.setTextSize(TypedValue.COMPLEX_UNIT_SP, font_size);
switch(DICT){
case SEMUA :
pic.loadUrl("file:///android_asset/img/Q.jpg");
content.setText(catatan.getString(0));
content.setLinkTextColor(Color.rgb(0x44, 0x44, 0xBB));
break;
default :
if(catatan.getString(3).equals("-")){
pic.loadUrl("file:///android_asset/img/Q.jpg");
pic.getSettings().setJavaScriptEnabled(true);
}else{
pic.loadUrl(catatan.getString(3));
}
content.setText("Catatan\t:\t"+catatan.getString(2));
content.setLinkTextColor(Color.rgb(0x44, 0x44, 0xBB));
break;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.drawable.readermenu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
float current_size = content.getTextSize();
switch (item.getItemId()) {
case R.id.zoomout:
content.setTextSize(TypedValue.COMPLEX_UNIT_PX, current_size*(float)(1/1.2));
break;
case R.id.zoomin:
content.setTextSize(TypedValue.COMPLEX_UNIT_PX, current_size*(float)1.2);
break;
default:
return super.onOptionsItemSelected(item);
}
return true;
}
@Override
public void onDestroy() {
// Don't forget to shutdown!
if (mTts != null) {
mTts.stop();
mTts.shutdown();
}
super.onDestroy();
}
/* Implements TextToSpeech.OnInitListener. */
public void onInit(int status) {
if (status == TextToSpeech.SUCCESS) {
switch(DICT) {
default:
case SEMUA:
case CARI:
SpeechStatus = mTts.setLanguage(Locale.ITALY);
break;
case ROUNDLE:
SpeechStatus = mTts.setLanguage(Locale.ITALY);
break;
}
if (SpeechStatus == TextToSpeech.LANG_MISSING_DATA || SpeechStatus == TextToSpeech.LANG_NOT_SUPPORTED) {
// Lanuage data is missing or the language is not supported.
speech.setBackgroundResource(R.drawable.speech_disabled);
} else {
speech.setBackgroundResource(R.drawable.speech_button);
}
} else {
speech.setBackgroundResource(R.drawable.speech_disabled);
speech.setEnabled(false);
speech.setClickable(false);
}
}
/* Install speech language if not available */
protected void installLanguage() {
// TODO Auto-generated method stub
new AlertDialog.Builder(this)
.setMessage("This language is not available.\nDo you want to install ?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
Intent installIntent = new Intent();
installIntent.setAction(TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
startActivity(installIntent);
}
})
.setNegativeButton("No", null)
.show();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
}
}
此行中的空指针
77：if（checkResult（））this.initUI（）;
101：catatan1 =＆＃34; SELECT * FROM Cari，其中较低（Nama_Pesawat）=较低（＆＃39;＆＃34; + text.replace（＆＃34;＆＃39;＆＃34;，＆ ＃34;＆＃39;＆＃39;＆＃34）+＆＃34;＆＃39;）＆＃34 ;;中断;
这是我的主要活动：
package com.rdsj.land;
import com.rdsj.land.R;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.TabActivity;
import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TabHost;
public class MainActivity extends TabActivity {
/** Called when the activity is first created. */
private AlertDialog.Builder builder;
private AlertDialog aboutDialog;
final String[] tab_menu = {
"Main Menu",
"Cari",
"Roundle"};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// call database helper
databasehelper bantuan = new databasehelper(MainActivity.this);
try {
bantuan.createDataBase();
} catch (Exception e) {
// 1000: handle exception
// tell when error copy
System.out.println("Copy Database gagal " + e.getMessage());
}
// tell when copy success
System.out.println("Copy Database Success");
Resources res = getResources(); // Resource object to get Drawables
TabHost tabHost = getTabHost(); // The activity TabHost
TabHost.TabSpec spec; // Resusable TabSpec for each tab
Intent intent; // Reusable Intent for each tab
// All
intent = new Intent().setClass(this, rinci.class);
intent.putExtra("DICT", 1);
spec = tabHost.newTabSpec("all").setIndicator(tab_menu[0] , res.getDrawable(R.drawable.tab_style)).setContent(intent);
tabHost.addTab(spec);
// English to Indonesian
intent = new Intent().setClass(this, keterangan.class);
intent.putExtra("DICT", 2);
spec = tabHost.newTabSpec("en2id").setIndicator(tab_menu[1], res.getDrawable(R.drawable.tab_style)).setContent(intent);
tabHost.addTab(spec);
// Indonesian to English
intent = new Intent().setClass(this, keterangan.class);
intent.putExtra("DICT", 3);
spec = tabHost.newTabSpec("id2en").setIndicator(tab_menu[2], res.getDrawable(R.drawable.tab_style)).setContent(intent);
tabHost.addTab(spec);
// Select Default Tab
tabHost.setCurrentTab(0);
// Create About Dialog
LayoutInflater inflater = (LayoutInflater) this.getSystemService(LAYOUT_INFLATER_SERVICE);
View layout = inflater.inflate(R.layout.about, (ViewGroup) findViewById(R.id.layout_root));
builder = new AlertDialog.Builder(this)
.setView(layout)
.setTitle("About")
.setNeutralButton("OK", null);
builder.setIcon(android.R.drawable.ic_dialog_info);
aboutDialog = builder.create();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.drawable.mainmenu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.setting:
Intent settingsActivity = new Intent(this.getBaseContext(), Setting.class);
startActivity(settingsActivity);
break;
case R.id.about:
aboutDialog.show();
break;
case R.id.exit:
MainActivity.this.finish();
break;
default:
return super.onOptionsItemSelected(item);
}
return true;
}
}
编辑： 我忘了我有databasehelper
package com.rdsj.land;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
public class databasehelper extends SQLiteOpenHelper{
// Direktori default
String DB_PATH =null;
// Variabel Nama Database
// Hanya mengganti di bagian ini saja
private static String DB_NAME = "PESAWAT.sqlite";
// Variabel SQLiteDatabase
private SQLiteDatabase myDataBase;
// Variabel Context Untuk menggabungkan Dengan Sctivity
private final Context myContext;
/**
* Constructor
* Untuk Mengakses Asset Pada Project
* @param context
*/
public databasehelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
DB_PATH="/data/data/"+context.getPackageName()+"/"+"databases/";
}
/**
* Membuat database kosong pada system dan menulis kembali sesuai dengan
* database kita yang berada pada Asset
* */
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
if(dbExist){
//Tidak mengerjakan Jika database Sudah Ada
}else{
// Memanggil Method dan Database Yang Telah Di Buat Di Direktori Default System
// Dari Method ini kita Dapat Menulis Database Kosong Dengan Database Kamu Dari Aplikasi
this.getReadableDatabase();
try {
close();
openDataBase();
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Cek jika database Tersedia untuk proses
* apakah Sudah Ada atau Belum
*/
private boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//Database Belum Tersedia
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copy Database Dari Asset Ke Database Kosong Yang Telah Dibuat.
* */
private void copyDataBase() throws IOException{
// Membuka Database Untuk proses Input Stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Alamat untuk Membuat Database Kosong
String outFileName = DB_PATH + DB_NAME;
// Membuka Database Kosong Sebagai Output Stream untuk Copy
OutputStream myOutput = new FileOutputStream(outFileName);
//Proses transfer byte dari input stream ke output stream
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Tutup Stream
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
//Open Database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close() {
if(myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
感谢您的帮助。
答案 0 :(得分：0)
将setContentView置于与onCreate方法相关联的onCreate内，并先被调用。
解决方式如下：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.keterangan); //here
/* Get Intent Parameter */
this.getIntentParameter();
......
.......
从您的方法中删除：
private void initUI() {
// TODO Auto-generated method stub
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
//removed from here
this.getWindow().setLayout(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
mTts = new TextToSpeech(this,this);