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幫我解決這個問題。我仍然堅持這一個。我真的不明白如何。我是新學習Java，這是我第一次構建apk。 固定應用程序中的數據庫無法打開。我有三個水龍頭。主菜單，search1，search2。這兩個標籤搜索都不起作用（不幸的是，應用程序已停止）。但我可以在主菜單上解鎖按鈕。在菜單搜索中Java NullPointerexception而不是按鈕主菜單
而且當我在oncreate中調用initUi方法。它不起作用。主菜單中的我的按鈕和標籤搜索無法打開。
這裏是我的logcat當我運行我的應用程序比點擊搜索1
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
這是我Keterangan.Java在這一行
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); } }空指針：如果（checkResult（））this.initUI（）; （）「;」break;「;」;「」;「」;「
這是我mainActivity：
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;
}
}
編輯： 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) {
}
}
感謝您的幫助。
你應該簡單地調用initUi方法的OnCreate –
感謝快速響應英寸我會嘗試 – rdsj