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我的應用程序崩潰每次我嘗試點擊一個按鈕，將文本輸入到listView，我得到的「java.lang.IllegalStateException：可能不執行android的方法：onClick「;我試過其他解決方案，但我似乎無法找到我自己的解決方案。任何幫助表示讚賞。應用程序崩潰 - java.lang.IllegalStateException：無法執行android的方法：onClick
MainActivity.java
public class MainActivity extends AppCompatActivity {
ListView listView;
ArrayList<String> arrayList;
ArrayAdapter<String> arrayAdapter;
String infoText;
int position;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Thread thread = new Thread(new Runnable(){
@Override
public void run(){
SharedPreferences getPrefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
boolean isFirstStart = getPrefs.getBoolean("started",true);
if(isFirstStart)
{
startActivity(new Intent (MainActivity.this,Intro.class));
SharedPreferences.Editor e = getPrefs.edit();
e.putBoolean("started", false);
e.apply();
}
}
});
thread.start();
listView = (ListView) findViewById(R.id.ListView);
arrayList = new ArrayList<>();
arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, arrayList);
listView.setAdapter(arrayAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent();
intent.setClass(MainActivity.this,EditMessageClass.class);
intent.putExtra(Intent_Constants.INTENT_INFO_DATA,arrayList.get(position).toString());
intent.putExtra(Intent_Constants.INTENT_ITEM_POSITION,position);
startActivityForResult(intent,Intent_Constants.INTENT_REQUEST_CODE_2);
}
});
}
public void onClick(View v){
Intent intent = new Intent();
intent.setClass(MainActivity.this,EditFieldClass.class);
startActivityForResult(intent,Intent_Constants.INTENT_REQUEST_CODE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
if (resultCode==Intent_Constants.INTENT_REQUEST_CODE){
infoText = data.getStringExtra(Intent_Constants.INTENT_INFO_FIELD);
arrayList.add(infoText);
arrayAdapter.notifyDataSetChanged();
}
else if(resultCode==Intent_Constants.INTENT_REQUEST_CODE_2){
infoText = data.getStringExtra(Intent_Constants.INTENT_CHANGED_INFO);
position = data.getIntExtra(Intent_Constants.INTENT_ITEM_POSITION,-1);
arrayList.remove(position);
arrayList.add(position,infoText);
arrayAdapter.notifyDataSetChanged();
}
}
}
Intent_Constants.java
public class Intent_Constants {
public final static int INTENT_REQUEST_CODE=1;
public final static int INTENT_RESULT_CODE=1;
public final static int INTENT_REQUEST_CODE_2=2;
public final static int INTENT_RESULT_CODE_2=2;
public final static String INTENT_INFO_FIELD="info_field";
public final static String INTENT_INFO_DATA="info_data";
public final static String INTENT_ITEM_POSITION="item_position";
public final static String INTENT_CHANGED_INFO="changed_info";
EditMessageClass.java
public class EditMessageClass extends AppCompatActivity {
String infoText;
int position;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_promo_layout);
Intent intent = getIntent();
infoText = intent.getStringExtra(Intent_Constants.INTENT_INFO_DATA);
position = intent.getIntExtra(Intent_Constants.INTENT_ITEM_POSITION,-1);
EditText infoData = (EditText) findViewById(R.id.info);
infoData.setText(infoText);
}
public void saveButtonClicked(View v){
String changedinfoText = ((EditText)findViewById(R.id.info)).getText().toString();
Intent intent = new Intent();
intent.putExtra(Intent_Constants.INTENT_CHANGED_INFO,changedinfoText);
intent.putExtra(Intent_Constants.INTENT_ITEM_POSITION, position);
setResult(Intent_Constants.INTENT_RESULT_CODE_2,intent);
finish();
}
}
EditFieldClass.java
public class EditFieldClass extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_promo_layout);
}
public void saveButtonClicked(View v){
String infoText = ((EditText)findViewById(R.id.info)).getText().toString();
if(infoText.equals("")){
}
else{
Intent intent = new Intent();
intent.putExtra(Intent_Constants.INTENT_INFO_FIELD,infoText);
setResult(Intent_Constants.INTENT_RESULT_CODE,intent);
finish();
}
}
}
日誌
FATAL EXCEPTION: main
Process: gabriel.com.prototype, PID: 15435
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
at gabriel.com.prototype.EditFieldClass.saveButtonClicked(EditFieldClass.java:27)
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
顯然，EditFieldClass的'add_promo_layout'佈局中沒有ID爲'info'的EditText。 –
檢查ID或只是發佈'add_promo_layout.xml'。 –