android 入门-Activity及 字体

    private Button sButton;
    private TextView mTextView;
    private Button fButton;
    private int[] sArray={,,,,};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_ex0313);

        mTextView=(TextView)findViewById(id.Ex0313DisplayText);
        sButton=(Button)findViewById(id.Ex0313SizeButton);
        sButton.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                Random mRandom=new Random();
                int mNum = mRandom.nextInt();
                mTextView.setTextSize(sArray[mNum]);
            }
        });        

        fButton=(Button)findViewById(id.Ex0313FontsButton);
        fButton.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Typeface fTypeface=Typeface.createFromAsset(getResources().getAssets(),"fonts/PentaGram'sMalefissent.ttf");
                mTextView.setTypeface(fTypeface);
            }
        });
    }

     <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/Ex0313DisplayText"
     android:layout_marginLeft="20dp"
        android:layout_marginTop="10dp"
        android:text="@string/hello_world" />
<Button android:id="@+id/Ex0313SizeButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="50dp"
        android:text="@string/ex0313sizebutton" />
<Button android:id="@+id/Ex0313FontsButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="100dp"
        android:text="@string/ex0313fontsbutton" />