android - 使用 subview 内的按钮将 subview 添加到主视图 - android

Question

我试图通过按下 subview 内的按钮将 subview 添加到主视图，但代码不起作用。知道问题是什么。我是 Android 初学者

这是主线性布局，其中添加了 + 和 - 按钮的子线性布局。我想通过按 + 在此下方添加另一行，然后按 - 将其删除。

这是主要布局:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/trainer_main"
android:layout_width="768dp"
android:layout_height="1280dp"
android:background="#121617"
android:orientation="vertical"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
tools:context=".TrainingProgrammer" >

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingBottom="25dip"
    android:textColor="#ffffff"
    android:textStyle="bold"
    android:text="@string/title_activity_training_programmer" />

<LinearLayout
    android:id="@+id/trainer_headline"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/interval_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="#ffffff"
        android:text="@string/training_programmer_interval" />

    <TextView
        android:id="@+id/exercise_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingLeft="10dip"
        android:paddingRight="95dip"
        android:textColor="#ffffff"
        android:text="@string/training_programmer_exercise" />

    <TextView
        android:id="@+id/second_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingRight="25dip"
        android:textColor="#ffffff"
        android:text="@string/training_programmer_time" />

    <TextView
        android:id="@+id/weight_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingRight="10dip"
        android:textColor="#ffffff"
        android:text="@string/training_programmer_weight" />

</LinearLayout>

这是子布局

   <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/trainer_progcontent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >


 <TextView
    android:id="@+id/interval_content"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textColor="#ffffff"
    android:textSize="14sp"
    android:ems="1"
    android:text="1" />

 <EditText
    android:id="@+id/exercise_content"
    android:layout_width="127dp"
    android:layout_height="wrap_content"
    android:textSize="14sp"
    android:singleLine="true"
    android:textColor="#ffffff"
    android:hint="@string/training_programmer_exercise_edit"
    android:ems="10" />

 <EditText
    android:id="@+id/time_content"
    android:layout_width="45dp"
    android:layout_height="wrap_content"
    android:hint="@string/training_programmer_time_edit"
    android:inputType="number"
    android:maxLength="2"
    android:textColor="#ffffff" />

<EditText
    android:id="@+id/weight_content"
    android:layout_width="45dp"
    android:layout_height="wrap_content"
    android:hint="@string/training_programmer_weight_edit"
    android:inputType="number"
    android:maxLength="2"
    android:textColor="#ffffff" />

<Button
    android:id="@+id/button_minus"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="30dp"
    android:layout_height="30dp"
    android:layout_marginLeft="20dp"
    android:background="@drawable/minus2" />

<Button
    android:id="@+id/button_plus"
    style="?android:attr/buttonStyleSmall"
    android:layout_width="30dp"
    android:layout_height="30dp"
    android:layout_marginLeft="20dp"
    android:background="@drawable/plus2" />

代码如下:

package ca.cruxtec.cruxtectrainer;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;


public class ProgrammerActivity extends ActionBarActivity {

private Button button_plus_define;
private Button button_minus_define;

static private final int MAX_NO_EXER = 30;
private int i = 1;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_programmer);

    final LinearLayout programmer_main_layout = (LinearLayout)findViewById(R.id.trainer_main);
    //LinearLayout sequence_layout = (LinearLayout)findViewById(R.id.trainer_progcontent);

    // Layout inflation for addition of the child view to the main view
    final View adding_child = getLayoutInflater().
    inflate(R.layout.sequence,   programmer_main_layout, false);
    programmer_main_layout.addView(adding_child);

    // Plus button
    button_plus_define = (Button)findViewById(R.id.button_plus);
    button_plus_define.setOnClickListener(new View.OnClickListener() {
        public void onClick(View arg0) {
            i++;
            programmer_main_layout.addView(adding_child);

           /* Toast.makeText(getApplicationContext(),
                    "i is :" + i, Toast.LENGTH_LONG).show();*/
        }
    });

    // minus button
    button_minus_define = (Button)findViewById(R.id.button_minus);
    button_minus_define.setOnClickListener(new View.OnClickListener() {
        public void onClick(View arg0) {
            /*if(i>2) i--;
            else {

                Toast.makeText(getApplicationContext(),
                        "i is less than 2:" , Toast.LENGTH_LONG).show();

            }
            Toast.makeText(getApplicationContext(),
                    "i is :" +i , Toast.LENGTH_LONG).show();*/

        }
    });



 }


 @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_programmer, menu);
    return true;
  }

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

      return super.onOptionsItemSelected(item);
 }
 }

应用程序崩溃是因为有

programmer_main_layout.addView(adding_child);

+ 按钮内

这里是主要错误:

30799-30799/ca.cruxtec.cruxtectrainer E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.

Answer 1

每次添加一个 View 作为另一个 View 的 subview 时，它应该是一个较新的 View 。但是您每次都添加相同的引用“adding_child”。我希望您理解为什么会出现“指定的 child 已经有 parent ”的错误。