我想通过单击音频图像进行搜索并说出我要搜索的内容，但是我遇到了尝试在空对象上调用虚拟方法'void android.widget.ImageButton.setOnClickListener'的常见错误参考，我不知道为什么要得到它
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.xbxvxe.rndfy, PID: 4436
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xbxvxe.rndfy/com.xbxvxe.rndfy.activity.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.xbxvxe.rndfy.activity.MainActivity.onCreate(MainActivity.java:176)
at android.app.Activity.performCreate(Activity.java:7009)
at android.app.Activity.performCreate(Activity.java:7000)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2731)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
在此行btnSpeak.setOnClickListener(new View.OnClickListener()
我的课是这样的：
public class MainActivity extends AppCompatActivity{
// URL
String URL= AppConfig.URL_GetFolders;
ArrayList<String> Folders;
// list view
ListView lv;
// Search EditText
EditText inputSearch;
private ImageButton btnSpeak;
private final int REQ_CODE_SPEECH_INPUT = 100;
ArrayAdapter<String> lvArrayAdapter;
// Hashmap
HashMap<Integer,String> lvMap = new HashMap<Integer, String>();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.folder_activity);
Folders=new ArrayList<>();
// declaring listview refs
lv= (ListView) findViewById(R.id.folder_Name);
inputSearch = (EditText) findViewById(R.id.inputSearch);
btnSpeak = (ImageButton) findViewById(R.id.btnSpeak);
// List view section
loadlvFolders(URL);
lv.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
String folder = lv.getItemAtPosition( lv.getSelectedItemPosition()).toString();
String id = lvMap.get(lv.getSelectedItemPosition());
Toast.makeText(getApplicationContext(),folder,Toast.LENGTH_LONG).show();
String newReq= new StringBuilder().append(AppConfig.URL_GetFoldersFK).append(id).toString();
Log.d("Request show",newReq);
Intent intent = new Intent(MainActivity.this, BuildingsListActivity.class);
// Sending value to another activity using intent.
intent.putExtra("FolderId", newReq);
startActivity(intent);
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
// DO Nothing here
}
});
// hide the action bar
btnSpeak.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
promptSpeechInput();
}
});
/*** Enabling Search Filter* */
inputSearch.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
// When user changed the Text
MainActivity.this.lvArrayAdapter.getFilter().filter(cs);
}
@Override
public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
int arg3) {
// TODO Auto-generated method stub
}
@Override
public void afterTextChanged(Editable arg0) {
// TODO Auto-generated method stub
}
});
init(savedInstanceState);
}
// listview function
private void loadlvFolders (String url) {
RequestQueue requestQueue=Volley.newRequestQueue(getApplicationContext());
StringRequest stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try{
JSONObject jsonObject = new JSONObject(response);
JSONArray jsonArray=jsonObject.getJSONArray("data");
for(int i=0;i<jsonArray.length();i++){
JSONObject jsonObject1 = jsonArray.getJSONObject(i);
String dossier = jsonObject1.getString("nom");
String id = jsonObject1.getString("id");
lvMap.put(i,id);
Folders.add(dossier);
}
ArrayAdapter<String> lvArrayAdapter = new ArrayAdapter<String>
(MainActivity.this, android.R.layout.simple_list_item_1, Folders);
lv.setAdapter(lvArrayAdapter);
}catch (JSONException e){
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
int socketTimeout = 30000;
RetryPolicy policy = new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
stringRequest.setRetryPolicy(policy);
requestQueue.add(stringRequest);
}
/**
* Showing google speech input dialog
* */
private void promptSpeechInput() {
Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE, Locale.getDefault());
intent.putExtra(RecognizerIntent.EXTRA_PROMPT,
getString(R.string.speech_prompt));
try {
startActivityForResult(intent, REQ_CODE_SPEECH_INPUT);
} catch (ActivityNotFoundException a) {
Toast.makeText(getApplicationContext(),
getString(R.string.speech_not_supported),
Toast.LENGTH_SHORT).show();
}
}
/**
* Receiving speech input
* */
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case REQ_CODE_SPEECH_INPUT: {
if (resultCode == RESULT_OK && null != data) {
ArrayList<String> result = data
.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
inputSearch.setText(result.get(0));
}
break;
}
}
}
}
答案 0 :(得分：1)
这意味着您的ImageButton没有正确初始化。 请检查您的xml，您已正确遵循xml中提到的名称。
答案 1 :(得分：0)
尝试使用ImageView而不是ImageButton并将其设置为onClickListner。