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好的，所以我已經在這個幾個小時了，不能讓它工作。 基本上，我想從可點擊的列表視圖調用一個意圖。我展示的車型，它是名單上的代碼，當你點擊，你應該被帶到另一個屏幕上編輯了汽車的性能，但是，我beggining認爲這是不可能的Android自定義列表視圖點擊 - 如何調用意圖而不崩潰？
listAdapter = new ArrayAdapter<String>(this, R.layout.simplerow, arrayListCarros);
mainListView.setAdapter(listAdapter);
db.close();
mainListView.setClickable(true);
mainListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) {
Intent i = new Intent(listagemcarro.this,com.example.trabalhosql.edicao.class);
startActivity(i);
}
});
代碼的其餘部分：
public class listagemcarro extends Activity {
Button buttonCadastro;
Button buttonListagem;
Button buttonBusca;
Button button1;
Intent itListagem = new Intent();
Intent itCadastro = new Intent();
Intent itBusca = new Intent();
//Intent itEdicao = new Intent();
Intent itEdicao2 = new Intent();
String id="";
public SQLiteDatabase db;
public String BANCO = "banco.db";
public String TABELA = "carro";
int posicao=123123;
private ListView mainListView ;
private ArrayAdapter<String> listAdapter ;
public void toast(int position){
Context context = getApplicationContext();
Toast toast = Toast.makeText(context, position, Toast.LENGTH_SHORT);
toast.show();
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listagemcarro);
Intent itRecebeParametros = getIntent();
if(itRecebeParametros != null){
id = itRecebeParametros.getStringExtra("id");
}
db = openOrCreateDatabase(BANCO, Context.MODE_PRIVATE, null);
Cursor linhas = db.query(TABELA, new String[] {"ID_PESSOA, MODELO"},"id_pessoa = '"+id+"'", null, null, null, null);
mainListView = (ListView) findViewById(R.id.mainListView);
ArrayList <String>arrayListCarros = new ArrayList<String>();
if(linhas.moveToFirst()){
do{
arrayListCarros.add(linhas.getString(0) +" " + linhas.getString(1));
}
while(linhas.moveToNext());
}
listAdapter = new ArrayAdapter<String>(this, R.layout.simplerow, arrayListCarros);
mainListView.setAdapter(listAdapter);
db.close();
mainListView.setClickable(true);
mainListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) {
Intent i = new Intent(listagemcarro.this,com.example.trabalhosql.edicao.class);
startActivity(i);
}
});
}
錯誤
11-19 23:18:09.136: W/dalvikvm(1784): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
11-19 23:18:09.136: E/AndroidRuntime(1784): Uncaught handler: thread main exiting due to uncaught exception
11-19 23:18:09.147: E/AndroidRuntime(1784): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.trabalhosql/com.example.trabalhosql.edicao}: java.lang.NullPointerException
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.os.Handler.dispatchMessage(Handler.java:99)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.os.Looper.loop(Looper.java:123)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.app.ActivityThread.main(ActivityThread.java:4363)
11-19 23:18:09.147: E/AndroidRuntime(1784): at java.lang.reflect.Method.invokeNative(Native Method)
11-19 23:18:09.147: E/AndroidRuntime(1784): at java.lang.reflect.Method.invoke(Method.java:521)
11-19 23:18:09.147: E/AndroidRuntime(1784): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
11-19 23:18:09.147: E/AndroidRuntime(1784): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
11-19 23:18:09.147: E/AndroidRuntime(1784): at dalvik.system.NativeStart.main(Native Method)
11-19 23:18:09.147: E/AndroidRuntime(1784): Caused by: java.lang.NullPointerException
11-19 23:18:09.147: E/AndroidRuntime(1784): at com.example.trabalhosql.edicao.onCreate(edicao.java:42)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-19 23:18:09.147: E/AndroidRuntime(1784): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
11-19 23:18:09.147: E/AndroidRuntime(1784): ... 11 more
edicao.class
package com.example.trabalhosql;
import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class edicao extends Activity {
String id="";
String modeloCarro = "";
TextView textViewCarroEscolhido;
public SQLiteDatabase db;
public String BANCO = "banco.db";
public String TABELA = "carro";
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listagemcarro);
Intent itRecebeParametros = getIntent();
if(itRecebeParametros != null){
id = itRecebeParametros.getStringExtra("id");
modeloCarro = itRecebeParametros.getStringExtra("modeloCarro");
}
textViewCarroEscolhido = (TextView) findViewById(R.id.textViewCarroEscolhido);
textViewCarroEscolhido.setText(modeloCarro);
}
}
不起作用，它們基本上是等效的代碼。 – tehort
你可以發佈'edicao.class'的OnCreate嗎？第42行是什麼？那裏似乎有些東西。 – mango
好吧，我用代碼編輯了我的文章，但我不認爲edicao.class是一個問題，我可以通過一個普通的按鈕來完美地調用它。 – tehort