Question

我的LinearLayout / View排列有问题。我想在我的LinearLayout和我的TextView（像WhatsApp有）之间有一个空格。我试图用LayoutParams设置边距，但它没有用。这是我的代码：

public void sendMessage(View v) {
    String actualMessage = textMessage.getText().toString();
    TextView message = new TextView(this);
    LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)message.getLayoutParams();
    message.setText(actualMessage);
    message.setGravity(Gravity.RIGHT);
    message.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 20);
    message.setBackgroundColor(getResources().getColor(R.color.orange));
    params.setMargins(0, 0, 0, 0);
    message.setLayoutParams(params);
    linearLayout.addView(message);
}

Answer 1

由于这两行，你有NPE

TextView message = new TextView(this);//orphan
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)
             message.getLayoutParams();//how can he have a parental care

你看到了你的问题

View.getLayoutParams()返回父级为特定孩子设置的布局参数，（-parental care）

更改为

public void sendMessage(View v) {
String actualMessage = textMessage.getText().toString();
TextView message = new TextView(this);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
  LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.
                   WRAP_CONTENT);//use what you want
message.setText(actualMessage);
params.gravity = Gravity.RIGHT;
message.setTextSize(TypedValue.COMPLEX_UNIT_DIP, 20);
message.setBackgroundColor(getResources().getColor(R.color.orange));
params.setMargins(0, 0, 0, 0);
message.setLayoutParams(params);
linearLayout.addView(message);
}

如果你使用Match_parent宽度忘记重力。

希望有所帮助

LinearLayout.LayoutParams的空指针异常

1 个答案: