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我正在嘗試爲Cricket製作評分簿應用程序。在應用程序的Team1.java類中，我嘗試填充A和B然後填充。它有一個EditText成員，用戶可以鍵入玩家的名字，然後按下Add More按鈕將更多玩家添加到teamPlayers的ArrayList中。問題是，當我按下添加按鈕時，應用程序會崩潰。代碼在下面突出顯示。任何幫助，將不勝感激。添加更多按鈕不工作 - ScoreBook.java
Team1.java
package ammar.newscorebook;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class Team1 extends Activity {
\t private String teamName;
\t private static ArrayList<String> playerList = new ArrayList<String>();
\t
\t private EditText playerName;
\t private TextView playerCount;
\t private Button addButton;
\t private Button doneButton;
\t
\t @Override
\t protected void onCreate(Bundle savedInstanceState){
\t \t super.onCreate(savedInstanceState);
\t \t setContentView(R.layout.activity_populate);
\t \t
\t \t setTeamName();
\t \t setPlayerNames();
\t \t done();
\t }
\t
\t private void setTeamName() {
\t \t // TODO Gets the name from edittext and sets it to a variable
\t \t EditText editText = (EditText) findViewById(R.id.teamName);
\t \t editText.addTextChangedListener(new TextWatcher(){
\t \t \t @Override
\t \t \t public void afterTextChanged(Editable arg0) {
\t \t \t \t // TODO Auto-generated method stub
\t \t \t \t teamName = arg0.toString();
\t \t \t \t
\t \t \t }
\t \t \t @Override
\t \t \t public void beforeTextChanged(CharSequence arg0, int arg1,
\t \t \t \t \t int arg2, int arg3) {
\t \t \t \t // TODO Auto-generated method stub
\t \t \t \t
\t \t \t }
\t \t \t @Override
\t \t \t public void onTextChanged(CharSequence arg0, int arg1, int arg2,
\t \t \t \t \t int arg3) {
\t \t \t \t // TODO Auto-generated method stub
\t \t \t \t
\t \t \t }
\t \t \t
\t \t });
\t }
\t
\t private void setPlayerNames() {
\t \t // TODO set the player names one by one in the array
\t \t
\t \t \t playerName = (EditText) findViewById(R.id.playerName);
\t \t \t playerCount = (TextView) findViewById(R.id.player_count_textview);
\t \t \t
\t \t \t addButton = (Button) findViewById(R.id.add_button);
\t \t \t addButton.setOnClickListener(new View.OnClickListener() {
\t \t \t \t
\t \t \t \t @Override
\t \t \t \t public void onClick(View v) {
\t \t \t \t \t String s = playerName.getText().toString();
\t \t \t \t \t if(playerName.length() != 0){
\t \t \t \t \t \t playerList.add(s);
\t \t \t \t \t \t playerCount.setText(playerName.length());
\t \t \t \t \t \t playerName.setText(R.string.playername_hint); \t
\t \t \t \t \t }
\t \t \t \t }
\t \t \t });
\t \t }
\t \t \t
\t private void done() {
\t \t // TODO Takes to Team2 populate activity
\t \t doneButton = (Button) findViewById(R.id.done_button);
\t \t doneButton.setOnClickListener(new View.OnClickListener() {
\t \t \t
\t \t \t @Override
\t \t \t public void onClick(View v) {
\t \t \t \t Intent i = new Intent(Team1.this, Team2.class);
\t \t \t \t String text = "Team " + getTeamName() + " created";
\t \t \t \t Toast.makeText(Team1.this, text, Toast.LENGTH_SHORT).show();
\t \t \t \t startActivity(i);
\t \t \t \t
\t \t \t }
\t \t });
\t \t
\t }
\t public String getTeamName() {
\t \t return teamName;
\t }
\t
\t public ArrayList<String> getPlayerList() {
\t \t return playerList;
\t }
}MainActivity.java
package ammar.newscorebook;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
\t
\t private Button mButton1;
\t @Override
\t protected void onCreate(Bundle savedInstanceState) {
\t \t super.onCreate(savedInstanceState);
\t \t setContentView(R.layout.activity_main);
\t \t
\t \t mButton1 = (Button)findViewById(R.id.team1_populate_button);
\t \t mButton1.setOnClickListener(new View.OnClickListener() {
\t \t \t
\t \t \t @Override
\t \t \t public void onClick(View v) {
\t \t \t \t Intent i = new Intent(MainActivity.this, Team1.class);
\t \t \t \t startActivity(i);
\t \t \t \t
\t \t \t }
\t \t });
\t \t
\t }
}這裏有兩個XML文件。
activity_main.xml中
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_horizontal"
android:orientation="vertical">
<TextView
android:layout_marginBottom="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/welcome" />
<Button
style="?android:attr/buttonBarButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/team1_populate_button"
android:text="@string/populate_teams" />
<Button
style="?android:attr/buttonBarButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/match_info_button"
android:text="@string/match_info_label" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:textSize="30sp"
android:id="@+id/start_scoring_button"
android:text="@string/scorebook" />
</LinearLayout>activity_populate.xml
<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="5dp">
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/teamname_label" />
<EditText android:layout_margin="5dp" android:id="@+id/teamName" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10" android:hint="@string/teamname_hint">
<requestFocus />
</EditText>
<TextView android:id="@+id/textView2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="15dp" android:text="@string/playername_label" />
<EditText android:layout_margin="5dp" android:id="@+id/playerName" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10" android:inputType="textPersonName" android:hint="@string/playername_hint" />
<LinearLayout android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="5dp">
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Player Count: " />
<TextView android:id="@+id/player_count_textview" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="0" />
</LinearLayout>
<LinearLayout android:layout_marginTop="20dp" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center">
<Button style="?android:attr/buttonBarButtonStyle" android:id="@+id/add_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/add_button_label" />
<Button style="?android:attr/buttonBarButtonStyle" android:id="@+id/done_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/done_button_label" />
</LinearLayout>
</LinearLayout>