问题描述
假设我在 TextView
中有以下文本ADD TEST",如下所示
如您所见,TextView
中的文本与 TextView
的宽度和高度不同.
我想要的是在 TextView
看看几个 Paint
方法:
suppose I have the following text 'ADD TEST' inside TextView
as shown below
as you can see the text inside the TextView
does not have the same width and height as TextView
.
what I want is to get the x,y position of text inside the TextView
Take a look at a couple of Paint
methods: getTextBounds()
and measureText
. We can use these to determine the offset of the text within the TextView
. Once the offset within the TextView
is determined, we can add that to the location of the TextView
itself to determine the screen coordinates of the text if that is desired.
I have also found the article "Android 101: Typography" to be useful in understanding some of the complexities of typography.
The following example finds the bounds of the text within three TextViews
and draws a rectangle around the text. The rectangle contains the (x, y) coordinates of the text within the TextView
.
activity_main.xml
A simple layout for demonstration.
<android.support.constraint.ConstraintLayout
android:id="@+id/layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:background="@android:color/holo_blue_light"
android:padding="24dp"
android:text="Hello World"
android:textColor="@android:color/black"
android:textSize="50sp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:background="@android:color/holo_blue_light"
android:padding="24dp"
android:text="Hello Worldly"
android:textColor="@android:color/black"
android:textSize="50sp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@id/textView1" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:background="@android:color/holo_blue_light"
android:padding="24dp"
android:text="aaaaaaaaaa"
android:textColor="@android:color/black"
android:textSize="50sp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@id/textView2" />
</android.support.constraint.ConstraintLayout>
MainActivity.java
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
drawTextBounds((TextView) findViewById(R.id.textView1));
drawTextBounds((TextView) findViewById(R.id.textView2));
drawTextBounds((TextView) findViewById(R.id.textView3));
}
private void drawTextBounds(TextView textView) {
// Force measure of text pre-layout.
textView.measure(0, 0);
String s = (String) textView.getText();
// bounds will store the rectangle that will circumscribe the text.
Rect bounds = new Rect();
Paint textPaint = textView.getPaint();
// Get the bounds for the text. Top and bottom are measured from the baseline. Left
// and right are measured from 0.
textPaint.getTextBounds(s, 0, s.length(), bounds);
int baseline = textView.getBaseline();
bounds.top = baseline + bounds.top;
bounds.bottom = baseline + bounds.bottom;
int startPadding = textView.getPaddingStart();
bounds.left += startPadding;
// textPaint.getTextBounds() has already computed a value for the width of the text,
// however, Paint#measureText() gives a more accurate value.
bounds.right = (int) textPaint.measureText(s, 0, s.length()) + startPadding;
// At this point, (x, y) of the text within the TextView is (bounds.left, bounds.top)
// Draw the bounding rectangle.
Bitmap bitmap = Bitmap.createBitmap(textView.getMeasuredWidth(),
textView.getMeasuredHeight(),
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Paint rectPaint = new Paint();
rectPaint.setColor(Color.RED);
rectPaint.setStyle(Paint.Style.STROKE);
rectPaint.setStrokeWidth(1);
canvas.drawRect(bounds, rectPaint);
textView.setForeground(new BitmapDrawable(getResources(), bitmap));
}
}
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