android - 线性布局内的线性布局正在添加但不可见

Question

我在 xml 中有一个空的线性布局。我正在向它动态添加一些 TextView 。

一旦这些 TextView 超过 5 个，我就会在其中再创建一个线性布局，并将 TextView 添加到新创建的布局中。最后将这个新布局添加到主布局。

我可以添加，即在模拟器中它占据了那个空间，但不会在 TextView 中显示信息。

我的xml如下:

<?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" >

    <ScrollView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <LinearLayout
            android:id="@+id/dyn_layout"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:padding="10dip" >
        </LinearLayout>
    </ScrollView>

    <Button
        android:id="@+id/dyn_button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Add TextViews" />

</LinearLayout>

我的java文件如下:

import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

public class AddTextViewsDynamically extends Activity implements
        OnClickListener {

    Button button;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_textview_dynamically);

        button = (Button) findViewById(R.id.dyn_button1);
        button.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.dyn_button1:
            LinearLayout layout = (LinearLayout) findViewById(R.id.dyn_layout);
            LinearLayout layout2 = null;
            LinearLayout layout3 = null;
            for (int i = 0; i < 10; i++) {
                if (i > 4) {
                    if (i == 5) {
                        layout2 = new LinearLayout(this);
                        layout2.setLayoutParams(new LayoutParams(
                                LayoutParams.FILL_PARENT,
                                LayoutParams.WRAP_CONTENT));
                        layout2.setOrientation(LinearLayout.VERTICAL);
                        layout2.setPadding(10, 60, 10, 10);
                        layout3 = new LinearLayout(this);
                        layout3.setLayoutParams(new LayoutParams(
                                LayoutParams.FILL_PARENT,
                                LayoutParams.WRAP_CONTENT));
                        layout3.setOrientation(LinearLayout.HORIZONTAL);
                        layout3.setPadding(10, 10, 10, 10);
                    }
                    System.out.println("**** Adding text view " + i);
                    TextView text = new TextView(this);
                    text.setText("The Value of i is :" + i);
                    text.setTextSize(12);
                    text.setGravity(Gravity.LEFT);
                    text.setLayoutParams(new LayoutParams(155,
                            LayoutParams.WRAP_CONTENT));
                    layout3.addView(text);

                    if (i == 9) {
                        System.out
                                .println("Added second linear layout to first");
                        layout2.setVisibility(View.VISIBLE);
                        layout2.addView(layout3);
                        layout.addView(layout2);
                    }
                } else {
                    System.out.println("###### Adding text view " + i);
                    TextView text = new TextView(this);
                    text.setText("The Value of i is :" + i);
                    text.setTextSize(12);
                    text.setGravity(Gravity.LEFT);
                    text.setLayoutParams(new LayoutParams(155,
                            LayoutParams.WRAP_CONTENT));
                    layout.addView(text);
                }
            }

        }

    }

}

我哪里错了？

Answer 1

您的主要 LinearLayout 设置为 Horizo​​ntal，因此前 5 个 TextView 和 layout2 显示在同一行上。将 Layout3 添加到 Layout2 使得 Layout3 从主线性布局的最后一个 TextView 的右侧显示。在 10 英寸的平板电脑上，我只能看到 LinearLayout 的前 2 个元素。也许在较小的屏幕上您看不到它们。尝试使用

text.setLayoutParams(new LayoutParams(50, LayoutParams.WRAP_CONTENT));

代替

text.setLayoutParams(new LayoutParams(155, LaoutParams.WRAP_CONTENT));

你应该会看到所有的 TextView 。

编辑:在您的情况下，这应该可以解决问题；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" >

    <ScrollView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" >

        <LinearLayout
            android:id="@+id/dyn_layout"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:padding="10dip" >
        </LinearLayout>

        <LinearLayout
            android:id="@+id/dyn_layout2"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:visibility="gone"
            android:padding="10dip" >
        </LinearLayout>
    </ScrollView>

    <Button
        android:id="@+id/dyn_button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Add TextViews" />

</LinearLayout>

和代码:

@Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.dyn_button1:
            LinearLayout layout = (LinearLayout) findViewById(R.id.dyn_layout);
            LinearLayout layout2 = (LinearLayout) findViewById(R.id.dyn_layout2);
            LinearLayout layout3 = null;
            for (int i = 0; i < 10; i++) {
                if (i > 4) {
                    if (i == 5) {
                        layout2.setPadding(10, 60, 10, 10);
                        layout3 = new LinearLayout(this);
                        layout3.setLayoutParams(new LayoutParams(
                                LayoutParams.FILL_PARENT,
                                LayoutParams.WRAP_CONTENT));
                        layout3.setOrientation(LinearLayout.HORIZONTAL);
                        layout3.setPadding(10, 10, 10, 10);
                    }
                    System.out.println("**** Adding text view " + i);
                    TextView text = new TextView(this);
                    text.setText("The Value of i is :" + i);
                    text.setTextSize(12);
                    text.setGravity(Gravity.LEFT);
                    text.setLayoutParams(new LayoutParams(155,
                            LayoutParams.WRAP_CONTENT));
                    layout3.addView(text);

                    if (i == 9) {
                        System.out
                                .println("Added second linear layout to first");
                        layout2.setVisibility(View.VISIBLE);
                        layout2.addView(layout3);
                    }
                } else {
                    System.out.println("###### Adding text view " + i);
                    TextView text = new TextView(this);
                    text.setText("The Value of i is :" + i);
                    text.setTextSize(12);
                    text.setGravity(Gravity.LEFT);
                    text.setLayoutParams(new LayoutParams(155,
                            LayoutParams.WRAP_CONTENT));
                    layout.addView(text);
                }
            }

        }

    }