Question

有没有人知道如何执行或在运行时在android中进行活动布局有一个很好的参考？

以下是我的活动代码。我确定我只是忽略了在这里做点什么：

package com.isi.sa;

import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.TextView;

public class SimpleAssessmentTest extends Activity {
  LinearLayout layout;
  TextView question;

  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);

    layout = new LinearLayout(this);
    question = new TextView(this);

    layout.setLayoutParams(new ViewGroup.LayoutParams(-1,-1));
    layout.setBackgroundColor(R.color.blue);

    question.setLayoutParams(new ViewGroup.LayoutParams(-1,-2));
    question.setTextColor(R.color.green);
    question.setTextSize(1,14);

    question.setText("This is question1");
    layout.addView(question);

    setContentView(layout);
  }
}

正如您所看到的，我只是尝试使用单个文本视图添加线性布局（仅用于测试目的）但是，当活动开始时，我只得到一个带有应用名称标题栏的黑屏。< / p>

由于

Answer 1

您忘了设置contentView。你应该添加

setContentView(layout);

onCreate方法

的末尾

Answer 2

您可以查看以下网址：http://www.linux-mag.com/cache/7705/1.html。它有库小部件和自定义小部件。

编辑：

setBackgroundColor需要以适当的ARGB格式输入： 0xAARRGGBB 。每个AA，RR，GG和BB的范围从00（最小）到ff（最大）。

最基本的例子就在这里，它完美无瑕。以下是截图和代码（稍作修改）：

http://picturepush.com/public/3313522（旧）

package us.simpleit;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

public class SimpleGUI extends Activity {
    TextView tv;
    EditText et;
    LinearLayout ll;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //LinearLayout ll = new LinearLayout(this);
        ll = new LinearLayout(this);
        ll.setOrientation(android.widget.LinearLayout.VERTICAL);
        ll.setLayoutParams(new ViewGroup.LayoutParams(-1,-1));
        // ARGB: Opaque Red
        ll.setBackgroundColor(0x88ff0000);

        tv = new TextView(this);
        tv.setLayoutParams(new ViewGroup.LayoutParams(-1,-2));
        tv.setText("sample text goes here");
        // ARGB: Opaque Green
        tv.setBackgroundColor(0x5500ff00);
        ll.addView(tv);

        et = new EditText(this);
        et.setLayoutParams(new ViewGroup.LayoutParams(-1,-2));
        et.setText("edit me please");
        // ARGB: Solid Blue
        et.setBackgroundColor(0xff0000ff);
        ll.addView(et);

        Button btn = new Button(this);
        btn.setText("Go!");
        btn.setOnClickListener(new Button.OnClickListener() {
            public void onClick(View v) {
                tv.setText(et.getText().toString());
            }
        });

        ll.addView(btn);
        setContentView(ll);

        //setContentView(R.layout.main);
    }
}

Answer 3

下面演示了如何在不使用布局xml文件的情况下以编程方式创建视图和布局。它还会创建一个圆角矩形布局对象，围绕放置在其中的任何子对象绘制一个圆角矩形。

package android.example;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MessageScreen extends Activity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  int mainBackgroundColor = Color.parseColor("#2E8B57");
  int labelTextColor = Color.parseColor("#FF4500");
  int messageBackgroundColor = Color.parseColor("#3300FF");
  int messageTextColor = Color.parseColor("#FFFF00");

  DisplayMetrics metrics = new DisplayMetrics();
  getWindowManager().getDefaultDisplay().getMetrics(metrics);
  float density = metrics.density;
  int minMarginSize = Math.round(density * 8);
  int paddingSize = minMarginSize * 2;
  int maxMarginSize = minMarginSize * 4;

  TextView label = new TextView(this);
  /*
   * The LayoutParams are instructions to the Layout that will contain the
   * View for laying out the View, so you need to use the LayoutParams of
   * the Layout that will contain the View.
   */
  LinearLayout.LayoutParams labelLayoutParams = new LinearLayout.LayoutParams(
    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
  label.setLayoutParams(labelLayoutParams);
  label.setTextSize(TypedValue.COMPLEX_UNIT_SP, 18);
  label.setPadding(paddingSize, paddingSize, paddingSize, paddingSize);
  label.setText(R.string.title);
  label.setTextColor(labelTextColor);

  TextView message = new TextView(this);
  RoundedRectangle.LayoutParams messageLayoutParams = new RoundedRectangle.LayoutParams(
 LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  /*
   * This is one of the calls must made to force a ViewGroup to call its
   * draw method instead of just calling the draw method of its children.
   * This tells the RoundedRectangle to put some extra space around the
   * View.
   */
  messageLayoutParams.setMargins(minMarginSize, paddingSize,
    minMarginSize, maxMarginSize);
  message.setLayoutParams(messageLayoutParams);
  message.setTextSize(TypedValue.COMPLEX_UNIT_SP, paddingSize);
  message.setText(R.string.message);
  message.setTextColor(messageTextColor);
  message.setBackgroundColor(messageBackgroundColor);

  RoundedRectangle messageContainer = new RoundedRectangle(this);
  LinearLayout.LayoutParams messageContainerLayoutParams = new LinearLayout.LayoutParams(
    LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  messageContainerLayoutParams.setMargins(paddingSize, 0, paddingSize, 0);
  messageContainer.setLayoutParams(messageContainerLayoutParams);
  messageContainer.setOrientation(LinearLayout.VERTICAL);
  /*
   * This is one of the calls must made to force a ViewGroup to call its
   * draw method instead of just calling the draw method of its children.
   * This tells the RoundedRectangle to color the the exta space that was
   * put around the View as well as the View. This is exterior color of
   * the RoundedRectangle.
   */
  messageContainer.setBackgroundColor(mainBackgroundColor);
  /*
   * This is one of the calls must made to force a ViewGroup to call its
   * draw method instead of just calling the draw method of its children.
   * This is the interior color of the RoundedRectangle. It must be
   * different than the exterior color of the RoundedRectangle or the
   * RoundedRectangle will not call its draw method.
   */
  messageContainer.setInteriorColor(messageBackgroundColor);
  // Add the message to the RoundedRectangle.
  messageContainer.addView(message);

  //
  LinearLayout main = new LinearLayout(this);
  LinearLayout.LayoutParams mainLayoutParams = new LinearLayout.LayoutParams(
    LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  main.setLayoutParams(mainLayoutParams);
  main.setOrientation(LinearLayout.VERTICAL);
  main.setBackgroundColor(mainBackgroundColor);
  main.addView(label);
  main.addView(messageContainer);

  setContentView(main);
 }
}

RoundedRectangle布局对象的类如下所示：

/**
 *  A LinearLayout that draws a rounded rectangle around the child View that was added to it.
 */
package android.example;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.widget.LinearLayout;

/**
 * A LinearLayout that has rounded corners instead of square corners.
 * 
 * @author Danny Remington
 * 
 * @see LinearLayout
 * 
 */
public class RoundedRectangle extends LinearLayout {
 private int mInteriorColor;

 public RoundedRectangle(Context p_context) {
  super(p_context);
 }

 public RoundedRectangle(Context p_context, AttributeSet attributeSet) {
  super(p_context, attributeSet);
 }

 // Listener for the onDraw event that occurs when the Layout is drawn.
 protected void onDraw(Canvas canvas) {
  Rect rect = new Rect(0, 0, getWidth(), getHeight());
  RectF rectF = new RectF(rect);
  DisplayMetrics metrics = new DisplayMetrics();
  Activity activity = (Activity) getContext();
  activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
  float density = metrics.density;
  int arcSize = Math.round(density * 10);

  Paint paint = new Paint();
  paint.setColor(mInteriorColor);

  canvas.drawRoundRect(rectF, arcSize, arcSize, paint);
 }

 /**
  * Set the background color to use inside the RoundedRectangle.
  * 
  * @param Primitive int - The color inside the rounded rectangle.
  */
 public void setInteriorColor(int interiorColor) {
  mInteriorColor = interiorColor;
 }

 /**
  * Get the background color used inside the RoundedRectangle.
  * 
  * @return Primitive int - The color inside the rounded rectangle.
  */
 public int getInteriorColor() {
  return mInteriorColor;
 }

}

Answer 4

我不确定这个问题是否得到了回答，但我今天刚刚克服了同样的问题。 Viet谈到了上面的问题，但没有明确指出要检查你的颜色值。如果你像我一样来自J2ME背景，你可能会将你的颜色int值定义为0xRRGGBB，所以对于全红色，J2ME会将其定义为0xFF0000。但是，在Android上执行此操作将导致int值为0x00FF0000。因为Android使用的格式为0xAARRGGBB，因此Android中的值为0xFF0000（J2ME）实际上是（0x00FF0000），这是完全红色，完全透明，因此在屏幕上看不到。

我在您使用的代码中注意到上面question.setTextColor(R.color.green);此语句将分配在R文件中创建的id值，因此它可能是一个高数字，其值为0x7f050000，其中Alpha设置为低于FULL不透明。试试你的例子：

question.setTextColor( getResources().getColor( R.color.green ) );

这应该将文本颜色设置为R.color.green中的值而不是R.color.green的ID。

Android运行时布局教程

4 个答案:

编辑：