我编写了以下代码,但输出没有显示任何内容。没有任何异常抛出,也没有使用此代码绘制线条。请帮我,我错了???
主要类
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
View custom_view = (View) findViewById(R.id.custom_view);
Paint p = new Paint();
p.setColor(Color.BLACK);
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth((float)5);
Canvas canvas = new Canvas();
canvas.drawColor(Color.BLUE);
canvas.drawLine((float)0, (float)0, (float)100, (float)100, p);
custom_view.draw(canvas);
}
activity_main.xml中
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#00000010" >
<View
android:id="@+id/custom_view"
android:background="#cccccc"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" /></RelativeLayout>
答案 0 :(得分:1)
我认为问题在于您需要为View
尝试类似:
public class CustomView extends View{
private Paint p;
public CustomView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public CustomView(Context context){
super(context);
init();
}
private void init() {
p = new Paint();
p.setColor(Color.WHITE);
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(5);
p.setAntiAlias(true);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawLine(0, 0, 100, 100, p);
}
}
在您的Activity类上:
RelativeLayout mLayout;
CustomView mView;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mLayout = (RelativeLayout)findViewById(R.id.rootLayout);
mView = new CustomView(this);
mLayout.addView(mView);
}
并将Id设置为rootLayout
的相对布局。
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/rootLayout"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<View
android:id="@+id/custom_view"
android:background="#000000"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</RelativeLayout>
希望有所帮助。
答案 1 :(得分:0)
<强>布局强>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal" >
<RelativeLayout
android:id="@+id/camera_preview"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<com.example.drawingapp.CameraView
android:id="@+id/cameraView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" />
</RelativeLayout>
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="20dp"
android:layout_marginTop="152dp"
android:contentDescription="@string/app_name"
android:src="@drawable/ic_launcher" />
<Button
android:id="@+id/button_capture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:text="@string/capture" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginTop="152dp"
android:text="@string/app_name" />
</RelativeLayout>
自定义视图类
public class CameraView extends View {
private Paint p;
int width = 0;
int height = 0;
int pass = 0;
int xpos = 0;
int ypos = 0;
public CameraView(Context context) {
super(context);
// TODO Auto-generated constructor stub
p = new Paint();
p.setColor(Color.WHITE);
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(1);
p.setAntiAlias(true);
}
public CameraView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
p = new Paint();
p.setColor(Color.WHITE);
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(1);
p.setAntiAlias(true);
}
public CameraView(Context context, AttributeSet attrs) {
super(context, attrs);
p = new Paint();
p.setColor(Color.WHITE);
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(1);
p.setAntiAlias(true);
}
@Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
width = getWidth();
height = getHeight();
xpos = width / 5;
ypos = height / 5;
for (int i = 0; i < 5; i++) {
p.setColor(Color.argb(100, 255, 255, 255));
canvas.drawLine(xpos + (xpos * i), 0, xpos + (xpos * i),
height, p);
// canvas.drawLine(startX, startY, stopX, stopY, paint)
}
p.setStyle(Style.STROKE);
for (int i = 0; i < 5; i++) {
p.setColor(Color.argb(100, 255, 255, 255));
canvas.drawLine(0, (ypos * pass) + 5, width, (ypos * pass) + 5,
p);
pass++;
}
}
public void hide(){
Visibility visibility = new Visibility();
visibility.
}
}
活动类
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}