[英]Pass ListView values to multiple EditText in another Activity
[英]How to pass multiple edittext values into a Arraylist and then send it to another activity?
我试图将5个edittext值传递到Arraylist
,然后将其发送到另一个活动。 我使用Intent将其发送到下一个活动,但是它一直崩溃。 我收到此错误:
java.lang.NullPointerException:尝试从空数组读取
我认为我将值添加到arraylist的方式是错误的,或者在意图中发送arraylist
出现了问题。
活动1:
EditText p1, p2, p3, p4, p5;
ArrayList<String> playerList = new ArrayList<>();
BootstrapButton btnStart;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnStart = (BootstrapButton) findViewById(R.id.start);
p1 = (EditText) findViewById(R.id.player1);
p2 = (EditText) findViewById(R.id.player2);
p3 = (EditText) findViewById(R.id.player3);
p4 = (EditText) findViewById(R.id.player4);
p5 = (EditText) findViewById(R.id.player5);
playerList.add(p1.getText().toString());
playerList.add(p2.getText().toString());
playerList.add(p3.getText().toString());
playerList.add(p4.getText().toString());
playerList.add(p5.getText().toString());
btnStart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent myIntent = new Intent(MainActivity.this, GameActivity.class);
myIntent.putStringArrayListExtra("player_list", playerList);
MainActivity.this.startActivity(myIntent);
}
});
}
活动2:
TextView playerName;
ArrayList<String> playerList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
playerName = (TextView) findViewById(R.id.playerName);
Intent myIntent = getIntent();
if(myIntent != null){
playerList = myIntent.getStringArrayListExtra("player_list");
playerName.setText(playerList.get(0));
}
}
当我将其与硬编码数组值一起使用时,它不会崩溃,并且该值将在下一个活动中正确打印出来。
活动1:
String[] array1={"asd","fgh","dcf","dg","ere","dsf"};
Intent myIntent = new Intent(MainActivity.this, GameActivity.class);
myIntent.putExtra("player_list", array1);
MainActivity.this.startActivity(myIntent);
活动2:
Intent myIntent = getIntent();
if(myIntent != null){
String[] players = myIntent.getStringArrayExtra("player_list");
playerName.setText(players[2]);
}else{
System.out.println("Error!");
}
我想要做的是拥有一个像这样的Arraylist
["p1","p2","p3","p4","p5"]
,然后在下一个活动中检索该arraylist
并从该数组中打印出一个随机名称。
使用getStringArrayListExtra
而不是getStringArrayExtra
if(myIntent != null){
String[] players = myIntent.getStringArrayListExtra("player_list");
playerName.setText(players[2]);
}
在活动1中使用intent.putStringArrayListExtra
发送并在活动2中使用getStringArrayListExtra()
检索字符串ArrayList。
这是这样做的代码:
活动1:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnStart = (BootstrapButton) findViewById(R.id.start);
p1 = (EditText) findViewById(R.id.player1);
p2 = (EditText) findViewById(R.id.player2);
p3 = (EditText) findViewById(R.id.player3);
p4 = (EditText) findViewById(R.id.player4);
p5 = (EditText) findViewById(R.id.player5);
playerList.add(p1.getText().toString());
playerList.add(p2.getText().toString());
playerList.add(p3.getText().toString());
playerList.add(p4.getText().toString());
playerList.add(p5.getText().toString());
btnStart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent myIntent = new Intent(MainActivity.this, GameActivity.class);
myIntent.putStringArrayListExtra("player_list", playerList);
MainActivity.this.startActivity(myIntent);
}
});
}
活动2:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
playerName = (TextView) findViewById(R.id.playerName);
Intent myIntent = getIntent();
if(myIntent != null){
ArrayList<String> players = myIntent.getStringArrayListExtra("player_list");
playerName.setText(players.get(0));
}else{
System.out.println("Error!");
}
}
还要确保playerList被声明和初始化。 您的代码没有显示它已被声明或初始化。
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