我在以下if循环中得到空指针异常：
...
if (tmp_tag.getName().equals("Tags")) {
e.setText(stringBuilder.toString());
}
...
我甚至检查过标签是否正确设置为editTexts但仍然得到“空指针异常”。不知道我在代码中缺少什么。事实上，我甚至不知道如何调试应用程序来查找错误。请帮帮我......
这是我的活动的java代码：
package com.walletapp;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.ContentValues;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
public class AddRecords extends Activity {
Spinner spinner, spinner_tags;
SQLiteDatabase database;
ArrayList<String> spinner_list, tags_list, cat_field_list;
String[] tags;
ArrayList<CharSequence> selectedTags = new ArrayList<CharSequence>();
TextView tv_1, tv_2, tv_3, tv_4, tv_5, tv_6, tv_7, tv_8, tv_9, tv_10,
tv_11, tv_12, tv_13;
EditText et_1, et_2, et_3, et_4, et_5, et_6, et_7, et_8, et_9, et_10,
et_11, et_12, et_13;
TextView[] tv;
EditText[] et;
Button btn_save;
int cat_id;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_records);
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
tv_1 = (TextView) findViewById(R.id.textView1);
tv_2 = (TextView) findViewById(R.id.textView2);
tv_3 = (TextView) findViewById(R.id.textView3);
tv_4 = (TextView) findViewById(R.id.textView4);
tv_5 = (TextView) findViewById(R.id.textView5);
tv_6 = (TextView) findViewById(R.id.textView6);
tv_7 = (TextView) findViewById(R.id.textView7);
tv_8 = (TextView) findViewById(R.id.textView8);
tv_9 = (TextView) findViewById(R.id.textView9);
tv_10 = (TextView) findViewById(R.id.textView10);
tv_11 = (TextView) findViewById(R.id.textView11);
tv_12 = (TextView) findViewById(R.id.textView12);
tv_13 = (TextView) findViewById(R.id.textView13);
tv = new TextView[] { tv_1, tv_2, tv_3, tv_4, tv_5, tv_6, tv_7, tv_8,
tv_9, tv_10, tv_11, tv_12, tv_13 };
et_1 = (EditText) findViewById(R.id.editText1);
et_2 = (EditText) findViewById(R.id.editText2);
et_3 = (EditText) findViewById(R.id.editText3);
et_4 = (EditText) findViewById(R.id.editText4);
et_5 = (EditText) findViewById(R.id.editText5);
et_6 = (EditText) findViewById(R.id.editText6);
et_7 = (EditText) findViewById(R.id.editText7);
et_8 = (EditText) findViewById(R.id.editText8);
et_9 = (EditText) findViewById(R.id.editText9);
et_10 = (EditText) findViewById(R.id.editText10);
et_11 = (EditText) findViewById(R.id.editText11);
et_12 = (EditText) findViewById(R.id.editText12);
et_13 = (EditText) findViewById(R.id.editText13);
et = new EditText[] { et_1, et_2, et_3, et_4, et_5, et_6, et_7, et_8,
et_9, et_10, et_11, et_12, et_13 };
selectedTags = new ArrayList<CharSequence>();
build_tags_list();
btn_save = (Button) findViewById(R.id.buttonAddRecordsSave);
btn_save.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
loadDatabase();
String currentDate = new SimpleDateFormat("yyyy/MM/dd")
.format(Calendar.getInstance().getTime());
// ----------first insert into records_data table------------
Tag tmp_tag = (Tag) et_1.getTag();
ContentValues values = new ContentValues();
values.put("cat_id", tmp_tag.getCat_id());
values.put("tag_id", "0");
values.put("is_favourite", "0");
values.put("rec_name", et_1.getText() + "");
values.put("is_delete", "0");
values.put("create_date", currentDate);
values.put("update_date", "0");
database.insert("records_data", null, values);
values.clear();
// --------now insert the rest of the entries except "Tags" into
// records_fields_data table---------
// ----------------first we fetch rec_id from records_data
int rec_id = 0;
Cursor cursor = database.query("records_data",
new String[] { "rec_id" }, "rec_name=?",
new String[] { et_1.getText() + "" }, null, null, null);
while (cursor.moveToNext()) {
rec_id = cursor.getInt(0);
}
cursor.close();
// ---------------use rec_id to insert into records_fields_data
for (EditText e : et) {
Tag tmp = (Tag) e.getTag();
if (tmp.getName().equals("Tags")) {
continue;
} else {
values.put("rec_id", rec_id);
values.put("cat_field_id", "0");
values.put("field_value", e.getText() + "");
values.put("is_delete", "0");
values.put("create_date", currentDate);
values.put("update_date", "0");
database.insert("records_fields_data", null, values);
values.clear();
}
}
// --------now insert into record_tag_relation table
if (selectedTags.size() != 0)
for (CharSequence s : selectedTags) {
values.put("cat_id", cat_id);
values.put("tag_id", get_tag_id(s));
database.insert("record_tag_relation", null, values);
values.clear();
}
}
});
spinner = (Spinner) findViewById(R.id.spinnerAddRecords);
cat_field_list = new ArrayList<String>();
build_spinner_list();
spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
cat_id = getId(arg0.getItemAtPosition(arg2) + "");
generateUI(arg0.getItemAtPosition(arg2) + "");
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
public int get_tag_id(CharSequence s) {
int tag_id = 0;
Cursor cursor = database.query("tags", new String[] { "tag_id" },
"tag_name=?", new String[] { s + "" }, null, null, null);
while (cursor.moveToNext()) {
tag_id = cursor.getInt(0);
}
return tag_id;
}
protected void showSelectTagsDialog() {
boolean[] checkedTags = new boolean[tags.length];
int count = tags.length;
for (int i = 0; i < count; i++)
checkedTags[i] = selectedTags.contains(tags[i]);
DialogInterface.OnMultiChoiceClickListener tagsDialogListener = new DialogInterface.OnMultiChoiceClickListener() {
@Override
public void onClick(DialogInterface dialog, int which,
boolean isChecked) {
if (isChecked)
selectedTags.add(tags[which]);
else
selectedTags.remove(tags[which]);
onChangeSelectedTags();
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Select Tag(s)");
builder.setMultiChoiceItems(tags, checkedTags, tagsDialogListener);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.dismiss();
}
});
AlertDialog dialog = builder.create();
dialog.show();
}
public void onChangeSelectedTags() {
StringBuilder stringBuilder = new StringBuilder();
for (CharSequence tag : selectedTags)
stringBuilder.append(tag + ",");
Tag tmp_tag = null;
for (EditText e : et) {
tmp_tag = (Tag) e.getTag();
// Toast.makeText(getBaseContext(), e.getText()+"",
// Toast.LENGTH_SHORT).show();
if (tmp_tag.getName().equals("Tags")) {
e.setText(stringBuilder.toString());
}
}
}
private void build_tags_list() {
loadDatabase();
tags_list = new ArrayList<String>();
Cursor cursor = database.query("tags", new String[] { "tag_name" },
null, null, null, null, null);
while (cursor.moveToNext())
tags_list.add(cursor.getString(0));
cursor.close();
database.close();
tags = tags_list.toArray(new String[tags_list.size()]);
}
private void build_spinner_list() {
loadDatabase();
spinner_list = new ArrayList<String>();
spinner_list.add("Category");
Cursor cursor = database.query("category",
new String[] { "cat_description" }, null, null, null, null,
null);
while (cursor.moveToNext())
spinner_list.add(cursor.getString(0));
cursor.close();
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, spinner_list);
dataAdapter
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(dataAdapter);
database.close();
}
protected int getId(String string) {
loadDatabase();
int tmp_cat_id = 0;
Cursor cursor = database.query("category", new String[] { "cat_id" },
"cat_description=?", new String[] { string }, null, null, null);
while (cursor.moveToNext())
tmp_cat_id = cursor.getInt(0);
cursor.close();
database.close();
return tmp_cat_id;
}
protected void generateUI(String string) {
if (string.equals("Category")) {
Toast.makeText(getBaseContext(),
"Select the category to proceed further.",
Toast.LENGTH_SHORT).show();
for (EditText e : et)
e.setVisibility(View.GONE);
for (TextView t : tv)
t.setVisibility(View.GONE);
btn_save.setVisibility(View.GONE);
}
else {
loadDatabase();
cat_field_list.clear();
// ----------------fetch id of item selected in spinner
// int cat_id = 0;
// Cursor cursor = database.query("category",
// new String[] { "cat_id" }, "cat_description=?",
// new String[] { string }, null, null, null);
// while (cursor.moveToNext())
// cat_id = cursor.getInt(0);
// cursor.close();
// ----------------fetch cat_fields of the selected item in the
// spinner
Cursor cursor = database.query("category_fields",
new String[] { "field_name" }, "cat_id=?",
new String[] { cat_id + "" }, null, null, null);
while (cursor.moveToNext())
cat_field_list.add(cursor.getString(0));
cursor.close();
// -------------sort list in the format "Description",.....Rest of
// the fields.....,"Notes","Tags"
ArrayList<String> al_new_cat_field_id_list = new ArrayList<String>();
al_new_cat_field_id_list = sort_list(cat_field_list);
for (int i = 0; i < al_new_cat_field_id_list.size(); i++) {
tv[i].setVisibility(View.VISIBLE);
tv[i].setText(al_new_cat_field_id_list.get(i));
et[i].setVisibility(View.VISIBLE);
et[i].setTag(new Tag(cat_id,
get_cat_field_id(al_new_cat_field_id_list.get(i)),
al_new_cat_field_id_list.get(i)));
if (al_new_cat_field_id_list.get(i).equals("Tags")) {
et[i].setFocusable(false);
et[i].setFocusableInTouchMode(false);
et[i].setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
showSelectTagsDialog();
}
});
}
Tag tmp = (Tag) et[i].getTag();
Toast.makeText(
getBaseContext(),
"cat_id: " + tmp.getCat_id() + ", cat_field_id: "
+ tmp.getCat_field_id() + ", name: "
+ tmp.getName(), Toast.LENGTH_SHORT).show();
}
btn_save.setVisibility(View.VISIBLE);
database.close();
}
}
private ArrayList<String> sort_list(ArrayList<String> cat_field_list2) {
int count = 0;
ArrayList<String> al_tmp = new ArrayList<String>();
for (String s : cat_field_list2) {
if (s.equals("Description")) {
if (al_tmp.contains(s)) {
// ----do nothing
} else {
al_tmp.add(s);
}
} else if (s.equals("Notes")) {
continue;
} else if (s.equals("Tags")) {
continue;
} else {
if (al_tmp.contains(s)) {
// ----do nothing
} else {
al_tmp.add(s);
}
}
count++;
if (count == cat_field_list.size() - 2) {
al_tmp.add("Notes");
al_tmp.add("Tags");
}
}
return al_tmp;
}
private int get_cat_field_id(String string) {
loadDatabase();
int tmp_cat_field_id = 0;
Cursor cursor = database.query("category_fields",
new String[] { "cat_field_id" }, "field_name=?",
new String[] { string }, null, null, null);
while (cursor.moveToNext())
tmp_cat_field_id = cursor.getInt(0);
cursor.close();
database.close();
return tmp_cat_field_id;
}
private void loadDatabase() {
database = openOrCreateDatabase("WalletAppDatabase.db",
SQLiteDatabase.OPEN_READWRITE, null);
}
public class Tag {
int cat_id;
int cat_field_id;
String name;
public Tag(int tmp_cat_id, int tmp_cat_field_id) {
cat_id = tmp_cat_id;
cat_field_id = tmp_cat_field_id;
}
public Tag(int tmp_cat_id, int tmp_cat_field_id, String tmp_name) {
name = tmp_name;
cat_id = tmp_cat_id;
cat_field_id = tmp_cat_field_id;
}
int getCat_id() {
return cat_id;
}
int getCat_field_id() {
return cat_field_id;
}
String getName() {
return name;
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
finish();
startActivity(new Intent(AddRecords.this, AllRecords.class));
return true;
}
return super.onKeyDown(keyCode, event);
}
}
这是我的logcat输出：
03-21 18:27:09.790: D/AndroidRuntime(32189): Shutting down VM
03-21 18:27:09.790: W/dalvikvm(32189): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
03-21 18:27:09.821: E/AndroidRuntime(32189): FATAL EXCEPTION: main
03-21 18:27:09.821: E/AndroidRuntime(32189): java.lang.NullPointerException
03-21 18:27:09.821: E/AndroidRuntime(32189): at com.walletapp.AddRecords.onChangeSelectedTags(AddRecords.java:241)
03-21 18:27:09.821: E/AndroidRuntime(32189): at com.walletapp.AddRecords$3.onClick(AddRecords.java:211)
03-21 18:27:09.821: E/AndroidRuntime(32189): at com.android.internal.app.AlertController$AlertParams$4.onItemClick(AlertController.java:886)
03-21 18:27:09.821: E/AndroidRuntime(32189): at android.widget.AdapterView.performItemClick(AdapterView.java:284)
03-21 18:27:09.821: E/AndroidRuntime(32189): at android.widget.ListView.performItemClick(ListView.java:3382)
03-21 18:27:09.821: E/AndroidRuntime(32189): at android.widget.AbsListView$PerformClick.run(AbsListView.java:1696)
03-21 18:27:09.821: E/AndroidRuntime(32189): at android.os.Handler.handleCallback(Handler.java:587)
03-21 18:27:09.821: E/AndroidRuntime(32189): at android.os.Handler.dispatchMessage(Handler.java:92)
03-21 18:27:09.821: E/AndroidRuntime(32189): at android.os.Looper.loop(Looper.java:123)
03-21 18:27:09.821: E/AndroidRuntime(32189): at android.app.ActivityThread.main(ActivityThread.java:4627)
03-21 18:27:09.821: E/AndroidRuntime(32189): at java.lang.reflect.Method.invokeNative(Native Method)
03-21 18:27:09.821: E/AndroidRuntime(32189): at java.lang.reflect.Method.invoke(Method.java:521)
03-21 18:27:09.821: E/AndroidRuntime(32189): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-21 18:27:09.821: E/AndroidRuntime(32189): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-21 18:27:09.821: E/AndroidRuntime(32189): at dalvik.system.NativeStart.main(Native Method)
03-21 18:27:11.730: I/Process(32189): Sending signal. PID: 32189 SIG: 9
答案 0 :(得分：0)
我真的不知道，但你可以尝试以下方法：不要使用增强的for循环，尝试通常的for循环：
public void onChangeSelectedTags() {
StringBuilder stringBuilder = new StringBuilder();
for (CharSequence tag : selectedTags)
stringBuilder.append(tag + ",");
Tag tmp_tag = null;
for (int i=0;i<et.length;i++) {
tmp_tag = (Tag) et[i].getTag();
// Toast.makeText(getBaseContext(), e.getText()+"",
// Toast.LENGTH_SHORT).show();
if (tmp_tag.getName().equals("Tags")) {
e.setText(stringBuilder.toString());
}
}
}
错误是否仍然存在？
答案 1 :(得分：0)
我得到了答案,,,这里是如何...... 我正在通过“setTag（）”将标签设置为前5个EditTexts和我的增强型for循环 ，我试图获得第6个（依此类推）EditText的标签，当我从未设置那些标签时，我将如何获得这些标签。 我唯一的错误是，我忘了在我的if循环中插入“break”...感谢你们的支持......